M&M’s Peanut Butter Cake

Indulge in the sweetest celebration ever!

Some cakes are elegant and sophisticated. Others are pure, unadulterated fun! This M&M’s Peanut Butter Cake definitely falls into the latter category. It’s a celebration in every bite, a playful explosion of textures and flavors that brings together everyone’s favorite candy-coated chocolate treats with the creamy, nutty goodness of peanut butter, all nestled within a moist, flavorful cake.

The combination of chocolate, peanut butter, and colorful M&M’s taps into a sense of joyful nostalgia for many. It’s a pairing often associated with childhood treats, movie nights, and simple pleasures. Translating that classic combination into a homemade layer cake elevates it into something truly special, perfect for marking birthdays, holidays, or any occasion that calls for a dessert that’s as cheerful as it is delicious.

While it looks impressive with its vibrant M&M’s topping, this cake is designed to be approachable for home bakers. The chocolate cake recipe is straightforward, the peanut butter frosting is simple to whip up, and the assembly focuses on classic layer cake techniques. The real “wow” factor comes from the generous scattering of M&M’s, which adds a delightful crunch and bursts of color to every slice.

Whether you’re baking for a child’s birthday party, surprising a peanut butter and M&M’s enthusiast, or just want to bring a smile to people’s faces, this M&M’s Peanut Butter Cake is a guaranteed crowd-pleaser. It’s a dessert that tastes like pure happiness and looks like a party waiting to happen. Get ready to bake some joy!

The Fun Starts Here: Unpacking the Ingredients

For the Moist & Flavorful Chocolate Cake Layers:

This recipe uses cocoa powder and milk to create a tender, chocolatey base.

2 cups All-Purpose Flour: Provides the structure for the cake layers. Standard all-purpose flour works perfectly here.
1 cup Granulated Sugar: Sweetens the cake and helps create a moist crumb.
2 teaspoons Baking Powder: A chemical leavener that helps the cake rise, contributing to a light and airy texture.
1 teaspoon Salt: Balances the sweetness and enhances the chocolate and peanut butter flavors.
½ cup Unsweetened Cocoa Powder: Provides the chocolate flavor and color to the cake. Use unsweetened cocoa powder (natural or Dutch-process). Dutch-process will give a slightly darker, smoother chocolate flavor.
1 cup Whole Milk, at room temperature: Provides moisture and liquid for the batter. Using whole milk adds richness. Ensure it’s at room temperature so it emulsifies properly with the other ingredients, leading to a smoother batter.
2 large Eggs, at room temperature: Provide structure, richness, and help bind the batter. Using room temperature eggs helps them incorporate more evenly.
1 teaspoon Vanilla Extract: Enhances the chocolate flavor and adds overall depth to the cake.
1 cup Creamy Peanut Butter: This is added directly into the cake batter! It adds significant peanut butter flavor and contributes to a very moist, tender crumb. Use creamy peanut butter (not natural style) for consistent texture and easier mixing.
Based on the typical structure of cake recipes and the frosting recipe provided separately, it’s highly probable that this line “1 cup peanut butter frosting (recipe below)” is a typo in the cake ingredient list and belongs only in the frosting section or refers to using some of the prepared frosting later in assembly, not in the cake batter itself. I will proceed assuming this line is an error in the cake ingredient list as provided and will not include frosting in the cake batter instructions or discussion, but will include it in the frosting section.
1 cup M&M’s: These are primarily for decoration on top of the cake. Given the title “M&M’s Peanut Butter Cake,” it’s implied Peanut Butter M&M’s are preferred, but any type of M&M’s will add color and chocolatey crunch. The image shows a mix of classic M&M’s and peanut M&M’s. I will discuss using various types for decoration.

For the Creamy & Nutty Peanut Butter Frosting:

This frosting is easy to whip up and provides the perfect peanut butter counterpart to the chocolate cake.

½ cup Creamy Peanut Butter: The base of the frosting, providing that essential peanut butter flavor. Use conventional creamy peanut butter (not natural) for the best smooth consistency.
1 ½ cups Powdered Sugar: Sweetens and provides structure for the frosting. Sifting helps prevent lumps.
2 tablespoons Unsalted Butter, softened: Adds richness and creates a classic buttercream texture when combined with peanut butter and powdered sugar. It must be softened to room temperature for smooth mixing.
1 teaspoon Vanilla Extract: Enhances the peanut butter and sweet flavors.
2-4 tablespoons Whole Milk: Used to adjust the frosting consistency, making it smooth and spreadable/pipeable. Start with 2 tablespoons and add more gradually until the desired texture is reached.

For Decoration:

The colorful finish that makes this cake a celebration!

1 cup M&M’s: The star of the decoration! Use a generous amount. A mix of colors and types (Peanut Butter, Peanut, Plain) adds visual interest.
Additional frosting as desired: Used for swirls or other decorative elements on top.

Baking the Fun: Step-by-Step Guide

Bake the Chocolate Cake Layers (Part 1)

Prepare Pans & Preheat Oven: Preheat your oven to 350°F (180°C). Grease two 9-inch round cake pans and line the bottoms with parchment paper. Greasing and lining ensures the cakes don’t stick and release easily.
Combine Dry Ingredients: In a medium bowl, whisk together the 2 cups all-purpose flour, 1 cup granulated sugar, 2 teaspoons baking powder, and 1 teaspoon salt. Whisking helps combine ingredients and aerates them.
Combine Wet & Cocoa: In a large mixing bowl, whisk together the ½ cup unsweetened cocoa powder and 1 cup room temperature whole milk until completely smooth. Starting with the cocoa and liquid helps ensure the cocoa is fully dissolved and there are no dry pockets.
Add Eggs & Vanilla: Add the 2 large room temperature eggs to the large bowl with the cocoa mixture, one at a time, whisking well after each addition to incorporate. Whisk in the 1 teaspoon vanilla extract.
Combine Wet and Dry: Gradually add the dry ingredients (from the medium bowl) to the wet chocolate mixture in the large bowl. Whisk or mix with an electric mixer on low speed until just combined and smooth. Do not overmix. Overmixing develops gluten and can lead to a tough cake.
Pour & Smooth: Divide the cake batter evenly between the two prepared cake pans. Use a spatula or the back of a spoon to gently smooth the tops of the batter in the pans so the cakes bake evenly.
Bake: Bake in the preheated oven for 30-35 minutes or until a toothpick inserted in the center comes out clean. The cakes are done when they spring back lightly when gently pressed in the center, or a toothpick inserted in the center comes out clean.
Cool Cakes: Remove the cake pans from the oven and place them on a wire rack. Allow the cakes to cool in their pans for 10 minutes. This allows them to firm up slightly before handling. After 10 minutes, carefully invert the cakes onto the wire rack and remove the parchment paper. Allow the cake layers to cool completely on the wire rack before frosting and assembling. Frosting warm cakes will melt the frosting.

Make the Creamy Peanut Butter Frosting (Part 2)

Beat Peanut Butter & Butter: In a medium bowl (using an electric mixer is easiest), beat the ½ cup creamy peanut butter and 2 tablespoons softened unsalted butter until smooth and creamy. Ensure the butter is properly softened for a smooth result.
Add Powdered Sugar: Gradually add the 1 ½ cups powdered sugar, beating on low speed until incorporated. Scrape down the sides of the bowl as needed.
Add Vanilla: Beat in the 1 teaspoon vanilla extract until combined.
Adjust Consistency with Milk: Add the whole milk, 1 tablespoon at a time, beating after each addition, until the frosting reaches your desired consistency for spreading or piping. For spreading, you’ll need slightly less milk; for piping swirls, you might need a little more to make it smooth enough to go through a tip.

Assemble the Fun Cake (Part 3)

Prepare for Assembly: Ensure your cake layers are completely cool. Place one cake layer on your serving plate or cake stand.
Fill Layer: Spread a generous layer of the peanut butter frosting evenly over the top of the first cake layer, using an offset spatula.
Stack & Frost: Carefully place the second cake layer on top of the frosted first layer. Use the remaining frosting to frost the top and sides of the entire cake. You can aim for a smooth finish using an offset spatula or bench scraper, or leave it rustic.
Decorate with M&M’s: This is the fun part! Decorate the top and sides of the cake generously with the 1 cup of M&M’s. You can press them gently into the frosting on the sides and scatter them on top. Use additional frosting (if reserved or made extra) to pipe decorative swirls around the edges of the top and place M&M’s on or around the swirls as desired (as shown in the image).
Chill (Optional but Recommended): While this cake doesn’t require chilling to set like a cheesecake, refrigerating it for 15-30 minutes after frosting can help the frosting firm up slightly, making it easier to handle and allowing the flavors to meld.

Pro Tips for a Celebratory Cake

Room Temperature is Key:Ensure your milk, eggs, and butter (for frosting) are at room temperature. This helps ingredients emulsify smoothly for better cake texture and frosting consistency. For butter, soft but not melted is perfect.
Measure Dry Ingredients Accurately:Spoon flour and powdered sugar into measuring cups and level off with a straight edge. Don’t scoop directly from the bag, which can compact the ingredients. Using a kitchen scale for weighing is the most accurate method.
Don’t Overmix Cake Batter:After adding the dry ingredients to the wet, mix only until just combined. Overmixing develops gluten, leading to a tough cake.
Cool Cakes Completely:Ensure cake layers are fully cooled before frosting to prevent the frosting from melting.
Crumb Coat (Optional for Clean Finish):For a super clean look, apply a thin layer of frosting all over the cake (a “crumb coat”), chill for 15-20 minutes to set and trap crumbs, then apply the final thicker layer of frosting. This isn’t strictly necessary but helps achieve smooth sides.
Frosting Consistency:Add the milk to the peanut butter frosting gradually until you reach your desired consistency. For spreading, it can be a bit softer; for piping swirls, you need it firm enough to hold its shape but soft enough to pipe smoothly.
M&M’s Placement:Press M&M’s gently into the frosting. If decorating the sides, it helps if the frosting has firmed up slightly from chilling. The colors of plain M&M’s can sometimes bleed slightly onto the frosting, especially if the frosting is very moist or the cake sits for a long time; using Peanut M&M’s (which have a chocolate center that is less prone to bleeding color onto light frosting) can help minimize this, or add them closer to serving time.
Pan Preparation:Don’t skip greasing and lining your cake pans! This prevents the cakes from sticking and makes removal much easier.

Your Recipe Card for Fun Baking

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Details based on your recipe:

Prep Time: 20 minutes
Cook Time: 30-35 minutes
Total Time: Approx. 2 hours 35 minutes – 3 hours 35 minutes (Includes cooling time)
Yield: 10-12 servings
Category: Dessert, Cake, Baking, Celebration
Method: Bake, Frost, Assemble
Cuisine: American, Baking
Diet: N/A (Note: Contains dairy, eggs, gluten, peanuts, sugar, etc. Not suitable for Vegetarian [if using standard M&Ms with gelatin], Vegan, Gluten-Free, Low Calorie, Low Fat, Low Salt, Diabetic diets.)

M&M’s Peanut Butter Cake Recipe

Author: Beth May
Total Time: Approx. 2.5–3.5 hours (including cooling & assembly)
Yield: 10–12 servings 1x

Print Recipe

Description

Indulge in the sweetest celebration ever with this M&M’s Peanut Butter Cake! This fun dessert features moist chocolate cake, creamy peanut butter frosting, and a generous topping of colorful M&M’s. Perfect for birthdays and parties.

Ingredients

Scale

For the Chocolate Cake:

2 cups all-purpose flour
1 cup granulated sugar
2 teaspoons baking powder
1 teaspoon salt
1/2 cup unsweetened cocoa powder
1 cup whole milk, at room temperature
2 large eggs, at room temperature
1 teaspoon vanilla extract
1 cup creamy peanut butter
1 cup M&M’s (for decoration)

For the Peanut Butter Frosting:

1/2 cup creamy peanut butter
1 1/2 cups powdered sugar
2 tablespoons unsalted butter, softened
1 teaspoon vanilla extract
2–4 tablespoons whole milk

Instructions

Make the Cake Layers:

1. Preheat the oven to 350°F (180°C). Grease two 9-inch round cake pans and line with parchment paper.

2. In a medium bowl, whisk together:

Flour

Sugar

Baking powder

Salt

3. In a large bowl, whisk cocoa powder with milk until smooth.

4. Add eggs one at a time, whisking well after each addition.

5. Stir in vanilla extract and creamy peanut butter.

6. Gradually add the dry ingredients to the wet mixture, whisking until smooth.

7. Divide the batter evenly between the two prepared pans and smooth the tops.

8. Bake for 30–35 minutes or until a toothpick inserted in the center comes out clean.

9. Cool cakes in the pans for 10 minutes, then turn them out onto a wire rack to cool completely.

Make the Peanut Butter Frosting:

1. In a bowl, beat together peanut butter and softened butter until smooth.

2. Gradually add powdered sugar, beating until fluffy.

3. Mix in vanilla extract.

4. Add milk, 1 tablespoon at a time, until frosting reaches desired consistency

Assemble the Cake:

1. Place one cake layer on a serving plate or cake stand.

2. Spread a thick layer of peanut butter frosting on top.

3. Add the second cake layer and frost the top and sides with the remaining frosting.

4. Decorate with M&M’s as desired.

Notes

Bring eggs, milk, and butter to room temperature for better texture.
Avoid overmixing to keep the cake light and fluffy.
For a professional finish, apply a crumb coat, chill the cake, then apply the final frosting layer.
Add M&M’s just before serving to prevent color bleed.
Store covered at room temperature for 1–2 days or in the refrigerator for up to 5 days. Let it come to room temperature before serving.

Prep Time: 20 minutes
Cook Time: 30–35 minutes
Category: Dessert, Cake, Party
Method: Bake, Frost, Assemble
Cuisine: American

Keywords: M&M’s Cake, Peanut Butter Cake, Chocolate Peanut Butter Cake, Layer Cake, Birthday Cake, Party Cake, Easy Cake Recipe, Celebration Cake

More Sweet Treats You’ll Love:

Craving more delicious ways to celebrate with dessert? Check out these other recipes from Galmof.com:

Reese’s Chocolate Peanut Butter Cup Cheesecake: If you love the peanut butter and chocolate combination, this decadent baked cheesecake takes it to the next level!
Ultimate Chocolate Cake: Our go-to recipe for a classic chocolate cake, perfect for any occasion.
Easy No-Bake Coconut Balls: For a simple, fun, and easy-to-share treat that’s great for parties.
Ultimate Oreo Freakshake: Lean into the fun dessert theme with this over-the-top chocolate and cookie dessert drink!