Coffee Cake Recipe: Simple Coffee-Flavored Sponge Cake

A coffee-flavored sponge cake is one of the most satisfying ways to use coffee as a baking ingredient. The technique is identical to a standard genoise — the only modification is adding dissolved coffee to the batter. This recipe covers the sponge, a coffee buttercream, and the assembly.

Ingredients (15cm / 6-inch round, 2 layers)

Equipment

• 15cm (6-inch) round cake tin, preferably loose-bottomed
• Electric hand mixer or stand mixer
• 2 large mixing bowls
• Rubber spatula
• Fine mesh sieve for flour
• Wire cooling rack

Instructions

Step 1: Preparation

Preheat oven to 170°C (340°F). Line the cake tin with parchment. Dissolve instant coffee in hot water and let cool to room temperature. Melt butter with milk in a small bowl and keep warm (around 60°C / 140°F).

Step 2: Whip the eggs

In a large bowl set over a pot of simmering water (bain-marie, 40–50°C), whisk eggs and sugar with a hand mixer until the mixture reaches ribbon stage — when you lift the beaters, the batter should fall in a thick ribbon that holds its shape for about 10 seconds. Remove from heat and continue beating until the mixture is pale, thick, and cooled.

Step 3: Fold in flour

Sift the cake flour over the egg mixture in three additions, folding gently with a rubber spatula each time. Use a bottom-to-top scooping motion. Stop as soon as no streaks of flour remain — overmixing develops gluten and deflates the foam.

Combine the warm butter-milk mixture with the cooled coffee liquid. Pour this down the side of the bowl and fold quickly until just incorporated.

Step 4: Bake

Pour batter into the prepared tin. Drop the tin on the counter 2–3 times from a low height to release large bubbles. Bake at 170°C for 25–30 minutes. A skewer inserted in the center should come out clean.

Unmold immediately and cool completely on a wire rack before frosting.

Step 5: Make the buttercream

Beat room-temperature butter with a hand mixer until pale and fluffy, about 3 minutes. Add powdered sugar in 2–3 additions, beating well after each. Add the cooled espresso gradually, beating until smooth and creamy.

Step 6: Assemble

Slice the cooled sponge horizontally into 2–3 layers. Spread buttercream between each layer and stack. Apply a crumb coat to the outside, refrigerate briefly, then apply a final layer of buttercream. Dust with cocoa powder or instant coffee, or press whole coffee beans into the top.

Adjusting Coffee Intensity

Instant coffee	Flavor	Best for
1 tbsp (light)	Faint coffee note	Coffee-cautious guests
2 tbsp (standard)	Clear coffee flavor	General preference
3 tbsp (strong)	Bold, slightly bitter	Coffee enthusiasts

Storage

Refrigerate for up to 3–4 days. Remove from refrigerator 30 minutes before serving — buttercream firms up significantly when cold and needs time to soften to its best texture.

Summary

• Dissolve instant coffee in hot water before adding to batter — do not add powder directly
• Fold flour in; do not mix — overmixing is the primary failure mode
• Cool all liquid (coffee, espresso) completely before adding to buttercream
• Espresso-based buttercream produces noticeably more complex flavor than instant-based versions