Name: Chocolate Peanut Butter Cake for a Crowd
Prep time: 35 min
Cook time: 40 min
Total time: 1 h 15 min
Yield: 20 servings
Cuisine: American
Ingredients: 2 cups all-purpose flour; 2 cups granulated sugar; ¾ cup unsweetened cocoa powder; 2 teaspoons baking powder; 1 teaspoon baking soda; 1 teaspoon salt; 1 cup whole milk; 1 cup vegetable oil; 4 large eggs; 2 teaspoons vanilla extract; 1 cup boiling water; 1 ½ cups creamy peanut butter; ½ cup unsalted butter, softened; 2 cups powdered sugar; ⅓ cup heavy cream; ½ teaspoon salt (for frosting); ½ cup mini chocolate chips (for topping)

Hey y'all! If you're on the hunt for a show-stopping dessert that'll wow guests at your next party, potluck, or family get-together, this Chocolate Peanut Butter Cake for a Crowd is just what you need. It’s decadent, ultra-moist, and generously layered with a creamy peanut butter frosting your friends and family will rave about. This recipe is quick to prep, makes enough for a big group, and is just as easy as it is irresistible. Let’s get cooking!

Why You’ll Love This Chocolate Peanut Butter Cake for a Crowd

Bake once and serve up to 24—perfect for gatherings, parties, and celebrations.
Rich, chocolaty cake complemented by a luscious, salty-sweet peanut butter frosting.
Simple pantry ingredients and one-bowl mixing keep it stress-free.
Make ahead and storage-friendly, so entertaining is a breeze.
Easy to adapt with gluten-free or nut-free alternatives, making it crowd-safe.

Ingredients for Chocolate Peanut Butter Cake for a Crowd

3 cups (375g) all-purpose flour
2 ¼ cups (450g) granulated sugar
1 cup (85g) unsweetened cocoa powder
2 teaspoon baking powder
1 ½ teaspoon baking soda
1 teaspoon salt
1 cup (240ml) vegetable oil
4 large eggs, room temperature
2 cups (480ml) buttermilk, room temperature
2 teaspoon vanilla extract
1 cup (240ml) hot water

Peanut Butter Frosting:

1 cup (240g) unsalted butter, softened
2 cups (510g) creamy peanut butter
4 cups (480g) powdered sugar, sifted
½ cup (120ml) milk (plus more as needed)
1 teaspoon vanilla extract
¼ teaspoon salt

How to Make Chocolate Peanut Butter Cake for a Crowd

Step 1: Prep the Pan & Oven

Preheat your oven to 350°F (175°C). Grease a 12x18-inch (half-sheet) cake pan and line with parchment paper for easy removal.

Step 2: Mix the Batter

In a large mixing bowl, whisk together flour, sugar, cocoa powder, baking powder, baking soda, and salt. Add in the oil, eggs, buttermilk, and vanilla. Beat on medium speed until just combined. Slowly pour in the hot water and mix until the batter is smooth (expect it to be a bit thin).

Step 3: Bake the Cake

Pour the batter into your prepared pan, smoothing the top. Bake for 28-32 minutes, or until a toothpick inserted in the center comes out clean. Cool completely in the pan on a wire rack.

Step 4: Make the Peanut Butter Frosting

In a large bowl, beat softened butter and peanut butter until light and creamy. Gradually add powdered sugar, mixing on low, then medium speed. Beat in milk, vanilla, and salt. Adjust consistency with additional milk if needed until smooth and spreadable.

Step 5: Frost & Serve

Once the cake is cool, spread frosting generously over the top. Slice into 24 squares with a sharp knife and serve!

Notes for the Best Chocolate Peanut Butter Cake for a Crowd

Room-temperature eggs and buttermilk help your cake rise evenly for a fluffier texture.
Not sure about buttermilk? Make a substitute at home using milk and lemon juice—see how at Allrecipes.
For sturdier frosting that holds up to warm environments, chill the cake after frosting for 20-30 minutes before serving.