Introduction

This Chocolate Peanut Butter Cake is a decadent treat perfect for feeding a crowd. Moist, rich chocolate layers are complemented by a fluffy peanut butter buttercream, making every bite irresistible. Whether for a party or special occasion, this cake is sure to impress.

The image shows several thick square pieces of chocolate cake with light brown peanut butter frosting spread thickly on top. The cake base is dark brown and dense, while the frosting layer is smooth and creamy, covering each piece neatly. Each slice is decorated with small chopped nuts and broken pieces of peanut butter cups, which create a textured look on top. Dark chocolate sauce and peanut butter drizzle are swirled over the frosting and candies, making a shiny, rich contrast. The treats sit on white parchment paper over a white marbled surface. Photo taken with an iphone --ar 4:5 --v 7

Ingredients

1 3/4 cups plain/all-purpose flour
3/4 cup unsweetened cocoa powder
1 1/2 tsp baking powder
1 1/2 tsp baking soda (bi-carb soda)
2 cups white sugar (or caster/superfine sugar)
1 tsp cooking/kosher salt
2 large eggs
1 cup milk (low or full fat)
1/2 cup vegetable oil (or other plain flavored oil like canola, grapeseed, rapeseed, sunflower)
2 tsp vanilla extract
2 tsp instant coffee powder (optional)
1 cup boiling water
250g / 2 sticks unsalted butter, softened
4 cups (500 g) soft icing sugar / powdered sugar, sifted
1/2 cup (120 g) smooth peanut butter (spread style, not pure)
1/4 tsp cooking/kosher salt
1 tbsp milk
1/2 cup chocolate chips or melts (semi-sweet)
2 tbsp cream (thickened/heavy or pure, not low fat)
3 tbsp peanut butter, warmed to make it runny
120g / 4 oz mini Reese’s Peanut Butter Cups
10+ miniature Reese’s Peanut Butter Cups, halved
1/4 cup salted peanuts, finely chopped

Instructions

Step 1: Preheat your oven to 180°C / 350°F (160°C fan). Grease a 23 x 33 cm (9 x 13 inch) metal cake pan with butter, then line it with baking paper, allowing an overhang for easy removal.
Step 2: In a large bowl, sift together the flour, cocoa powder, baking powder, and baking soda. Add the sugar and salt, then whisk briefly to combine.
Step 3: Add the eggs, milk, vegetable oil, and vanilla extract to the dry ingredients. Whisk vigorously until the mixture is smooth and lump-free, about 30 seconds.
Step 4: Stir in the instant coffee powder (if using), then carefully add the boiling water. Whisk to combine; the batter will be very thin. Pour it evenly into the prepared cake pan.
Step 5: Bake for 45 minutes, or until a wooden skewer inserted into the center comes out clean. Let the cake cool in the pan for 10 minutes, then transfer to a wire rack to cool completely, about 2 hours.
Step 6: To make the peanut butter buttercream frosting, beat the softened butter on high speed for 3 minutes until fluffy. Gradually add the sifted icing sugar in three batches, starting on low speed to avoid a sugar cloud, then increasing speed until fully mixed.
Step 7: Once all icing sugar is incorporated, add the smooth peanut butter, salt, and milk. Beat on high speed for 3 minutes until light, fluffy, and spreadable.
Step 8: For the chocolate drizzle, combine the chocolate chips and cream in a small bowl. Microwave in 15-second bursts, stirring between, until smooth. Let cool for 10 minutes before use.
Step 9: Spread the peanut butter frosting evenly over the cooled cake, covering from edge to edge.
Step 10: Drizzle half of the chocolate drizzle and melted peanut butter randomly over the frosting. Scatter mini Reese’s Peanut Butter Cups on top, then drizzle with the remaining chocolate and peanut butter.
Step 11: Sprinkle finely chopped salted peanuts and halved miniature Reese’s around the cake for decoration. Serve immediately and cut into pieces sized to your liking.

Tips & Variations

Use instant coffee powder to enhance the chocolate flavor, but it’s optional if you prefer a pure chocolate taste.
For a richer cake, substitute full-fat milk and use high-quality cocoa powder.
If you don’t have Reese’s Peanut Butter Cups, use chopped regular peanut butter cups or your favorite chocolate peanut butter candy.
To prevent frosting from getting gritty, always sift your icing sugar before mixing.

Storage

Store leftover cake in an airtight container in the refrigerator for up to 5 days. Because the frosting firms up when cold, bring slices to room temperature before serving for the best texture and flavor.

How to Serve

The image shows several square pieces of rich dark chocolate cake with a thick, creamy light brown peanut butter frosting layer on top, about one layer thick. The frosting is drizzled with dark chocolate sauce and peanut butter sauce in irregular lines across each piece. Scattered on top are chopped peanuts and halved peanut butter cup candies, adding texture and color contrast with their brown and tan shades. The cake pieces are placed on white parchment paper over a white marbled surface, with some chocolate sauce smudges around. In the background, a white bowl filled with chocolate sauce and a silver spoon, along with some peanut butter cups, can be seen. photo taken with an iphone --ar 4:5 --v 7

Serve this delicious recipe with your favorite sides.

FAQs

Can I make this cake gluten-free?

Yes, you can substitute the all-purpose flour with a gluten-free baking blend. Make sure it contains xanthan gum or a similar binder for best results.

Is the coffee flavor strong in the cake?

No, the instant coffee powder is used in a small amount to deepen and enhance the chocolate flavor without imparting a noticeable coffee taste.