Butterfinger Recipe

Prepare

Preheat oven to 350°F (175°C). Grease and line the bottoms of three 8-inch round cake pans with parchment; lightly flour or spray with nonstick spray.

Dry ingredients

In a large bowl, sift or whisk together the flour, cocoa powder, baking powder, baking soda, salt, and granulated sugar until evenly combined.

Wet ingredients

In a separate bowl or large measuring cup, whisk together eggs, buttermilk, vegetable oil and vanilla extract until smooth.

Combine

Add the wet ingredients to the dry and mix gently until just combined. With the mixer running on low, slowly pour in hot brewed coffee and beat until batter is smooth and fairly thin (the hot coffee blooms the cocoa and thins the batter).

Bake

Divide batter evenly between the three prepared pans (use a scale or measure for even layers). Bake in the preheated oven for 22–28 minutes, or until a toothpick inserted into the center comes out with a few moist crumbs. Rotate pans halfway through if your oven is uneven.

Cool

Allow cakes to cool in pans for 10 minutes, then run a knife around edges, invert onto wire racks, remove parchment and cool completely before assembling (at least 1 hour). If layers dome, level with a serrated knife so they stack flat.

Soften & beat butter

In a large bowl with a mixer, beat the unsalted butter on medium speed until smooth and pale, about 2–3 minutes.

Add peanut butter

Add the creamy peanut butter and beat until fully incorporated and smooth, about 1–2 minutes.

Incorporate sugar

On low speed, gradually add confectioners' sugar, one cup at a time, scraping the bowl as needed. Once incorporated, increase speed to medium and beat until smooth.

Adjust consistency & flavor

Add the heavy cream a tablespoon at a time (3 tbsp total), vanilla extract and salt. Beat on medium-high for 1–2 minutes until light and fluffy. If buttercream is too thick, add up to 1 more tablespoon cream; if too thin, add small additional powdered sugar. Taste and add peanut butter extract (optional) for a stronger peanut butter note.

Heat cream

Place chopped chocolate in a heatproof bowl. In a small saucepan, bring heavy cream just to a simmer (do not boil).

Make ganache

Pour hot cream over chocolate, let sit for 1 minute, then gently stir until smooth and glossy. Stir in 1 tablespoon butter if desired for extra sheen. Allow ganache to cool at room temperature until thickened but still pourable for a drip (about 20–40 minutes depending on room temperature). Reserve about 1/3 cup for filling between layers and the rest for drip and decorating.

Chop candy

Roughly chop 6 Butterfinger bars into bite-sized pieces. Reserve 1 cup of smaller crushed pieces for topping. Toss the larger pieces lightly in 1–2 tablespoons of buttercream (optional) to help them adhere in the filling so they don't all sink to the bottom.

Level & soak (optional)

If cakes are domed, level layers so they are flat. Brush each layer lightly with simple syrup (about 1–2 tablespoons per layer) to keep moist; add the optional 1/2 tsp peanut butter extract to the syrup for extra flavor before brushing.

First layer

Place first cake layer on your cake board or serving plate. Spread about 3/4 cup peanut butter buttercream evenly over the layer, leaving a small margin at the edge (this prevents buttercream squeeze-out when stacking). Spoon 2–3 tablespoons of the cooled ganache in a ring toward the center and spread lightly, then sprinkle a third of the chopped Butterfinger pieces over the buttercream. Press gently to adhere.

Second layer

Place the second cake layer on top and repeat: spread 3/4 cup buttercream, a thin ring or smear of ganache (2–3 tablespoons), then another third of chopped Butterfinger pieces.

Top layer & crumb coat

Place top layer on. Use remaining buttercream to apply a thin crumb coat over the entire cake (about 1/2–3/4 cup). Chill the cake in the refrigerator for 20–30 minutes to set the crumb coat.

Final coat

Remove cake from fridge and apply a final, smooth layer of peanut butter buttercream (reserve about 1/2 cup for piping if desired). Smooth sides and top with an offset spatula. If you want clean edges for the ganache drip, chill briefly again so the buttercream is firm.

Ganache drip

Re-warm ganache if necessary (brief bursts in microwave, stirring between, avoid overheating) until pourable but not hot. Transfer ganache to a squeeze bottle or use a spoon. Starting at the chilled cake edge, apply small amounts to create drips that run down the sides. Once perimeter is done, spread remaining ganache on the center of the top and smooth gently toward the edges.

Decorate with Butterfinger pieces

While ganache is still slightly tacky, press the reserved crushed Butterfinger pieces around the top center and a few larger pieces on top or along the base as desired. Pipe any remaining peanut butter buttercream rosettes or borders and place small pieces on each rosette. Use melted extra chocolate for additional decoration (drizzle or patterns) and allow everything to set at room temperature (or chill briefly).

Once assembled, store cake in a cool place or refrigerated (covered) for up to 3–4 days. If refrigerated, bring to room temperature 30–60 minutes before serving for best texture. Slice with a hot, clean knife (dip in hot water and wipe between cuts) for clean slices.