Introduction

This Chocolate Brownie Cake with Peanut Butter Frosting is a rich, indulgent treat perfect for celebrations or any time you crave a decadent dessert. The fudgy brownie layers combined with creamy peanut butter frosting and a silky chocolate drip create a delicious harmony of flavors and textures.

A tall round cake with two main layers covered in smooth light brown frosting sits on a white scalloped cake stand. On top, a thick shiny dark chocolate glaze drips down the sides with chocolate sprinkles stuck to the glaze edges. The top is decorated with whole and halved chocolate peanut butter cups piled in the center, and more peanut butter cups are scattered around the base of the cake stand. The background is a white marbled texture. photo taken with an iphone --ar 4:5 --v 7

Ingredients

1 stick (113 grams) unsalted butter
8 ounces (227 grams) semisweet baking chocolate, chopped
1 cup (200 grams) granulated sugar
2/3 cup (133 grams) dark brown sugar
3/4 cup (95 grams) all-purpose flour
1 cup (85 grams) unsweetened natural cocoa powder
3/4 teaspoon baking powder
1/2 teaspoon fine sea salt
5 large eggs, at room temperature
1/2 cup fresh vegetable oil
1 teaspoon vanilla extract
2 sticks (227 grams) unsalted butter, at room temperature
1 cup (270 grams) creamy conventional peanut butter
1 teaspoon vanilla extract
1/8 teaspoon fine sea salt
2 1/2 cups (313 grams) powdered sugar, sifted
4 ounces (113 grams) semisweet or bittersweet chocolate, finely chopped
1/2 cup heavy cream
Chopped peanut butter cups (optional)

Instructions

Step 1: Preheat the oven to 350°F. Grease and line three 6-inch cake pans with parchment paper.
Step 2: In a heat-safe bowl, combine the butter and chopped chocolate. Microwave for 45 seconds, stir, then continue heating in 30-second bursts, stirring between each, until melted and smooth. Whisk in the granulated and brown sugars until combined, then let cool.
Step 3: In a small bowl, whisk together the flour, cocoa powder, baking powder, and salt.
Step 4: To the cooled chocolate mixture, whisk in the eggs one at a time, whisking vigorously for 30 seconds after each addition until well combined. Add the oil and vanilla extract and whisk to combine.
Step 5: Gently fold in the dry ingredients until just combined.
Step 6: Divide the batter evenly among the prepared pans. Tap the pans on the counter to release any air bubbles.
Step 7: Bake for 25 to 30 minutes, or until the cake tops are dry and a tester inserted comes out with a few moist crumbs. Avoid overbaking as the cakes will continue to cook after removal.
Step 8: Cool the cakes in the pans for 10 minutes, then turn out onto wire racks to cool completely. Wrap tightly and refrigerate up to 2 days if not assembling immediately.
Step 9: For the frosting, beat the room-temperature butter and peanut butter in a mixer on medium-high speed until light and fluffy, scraping down the bowl as needed.
Step 10: Add the vanilla, salt, and sifted powdered sugar. Continue beating until smooth and fluffy, about 3 minutes.
Step 11: To assemble, place one cake layer on your serving plate. Spread about 1/2 cup frosting over the top. Repeat with remaining layers, finishing with the top layer flat side up.
Step 12: Apply a thin crumb coat layer of frosting over the entire cake. Smooth any excess with a spatula. Refrigerate for 15 to 20 minutes to set.
Step 13: Spread the remaining frosting evenly over the chilled cake. Refrigerate again to firm.
Step 14: For the chocolate drip, place chopped chocolate in a heatproof bowl. Bring heavy cream to a simmer, remove from heat, and pour over the chocolate. Let sit for a few minutes, then stir until smooth.
Step 15: Let the ganache cool until thick but still pourable (about 10 minutes). Test by dripping a little on a glass. Adjust consistency by briefly microwaving or cooling as needed.
Step 16: Pour the ganache over the top of the cake, letting it drip down the sides naturally.
Step 17: Allow the ganache to set slightly before garnishing with chopped peanut butter cups, if desired.

Tips & Variations

Use room temperature eggs to help achieve a smooth batter and even bake.
For a nut-free version, substitute the peanut butter frosting with a classic chocolate buttercream.
If you don’t have a microwave, melt the chocolate and butter using a double boiler over simmering water.
Feel free to add a pinch of espresso powder to the batter to enhance the chocolate flavor.

Storage

Store the assembled cake covered at room temperature for up to 1 day or in the refrigerator for up to 3 days. Before serving, bring to room temperature for the best texture and flavor. Reheat slices gently in the microwave if desired.

How to Serve

This is a close-up of a thick, three-layer chocolate cake on a white plate with a ruffled edge, set on a white marbled surface. Each layer is dark and moist with light brown creamy frosting between them. The outside of the cake is covered smoothly in the same light brown frosting, with glossy dark chocolate ganache dripping from the top edge down the sides. The top is sprinkled with dark chocolate sprinkles, and several pieces of chocolate peanut butter cups are placed on top and around the base of the cake. The inside layers are clearly visible due to a large slice being removed, showing the texture of the cake and frosting. photo taken with an iphone --ar 4:5 --v 7

Serve this delicious recipe with your favorite sides.

FAQs

Can I make the brownie cake layers in advance?

Yes, the brownie cake layers can be baked up to 2 days ahead and stored wrapped tightly in the refrigerator. Bring them to room temperature before assembling.

What can I use instead of peanut butter frosting?

You can replace the peanut butter frosting with a chocolate or vanilla buttercream if you prefer or have nut allergies.