Step 1. Preheat the Oven and Prepare the Cake Pans

Preheat your oven to 180°C (350°F). Grease and line two 8-inch round cake pans with parchment paper.

Step 2. Dissolve the Coffee

In a small bowl, dissolve 2 tablespoons of instant coffee granules in 1 tablespoon of boiling water. Stir until smooth and set aside to cool slightly.

Step 3. Cream Butter and Sugar

In a large mixing bowl, beat the softened butter and caster sugar together until light and fluffy, about 2-3 minutes.

Step 4. Add Eggs and Coffee

Add the eggs one at a time, mixing well after each addition. Pour in the dissolved coffee mixture and mix until combined.

Step 5. Add Flour, Baking Powder, and Walnuts

Sift in the self-raising flour and baking powder, and gently fold them into the wet ingredients. Then, fold in the chopped walnuts until evenly distributed in the batter.

Step 6. Divide Batter and Bake

Divide the batter evenly between the prepared cake pans. Smooth the tops with a spatula, then bake in the preheated oven for 25-30 minutes, or until a skewer inserted into the center of each cake comes out clean.

Step 7. Cool the Cake Layers

Allow the cakes to cool in the pans for 10 minutes, then transfer to a wire rack to cool completely.

Step 8. Make the Coffee Buttercream Frosting

In a mixing bowl, beat the softened butter until smooth. Gradually add the icing sugar, beating until light and creamy. Dissolve 1 tablespoon of instant coffee granules in 1 tablespoon of boiling water, then add to the frosting mixture and beat until well incorporated.

Step 9. Assemble the Cake

Place one cake layer on a serving plate. Spread a layer of coffee buttercream frosting on top. Place the second cake layer on top, then spread the remaining frosting over the top and sides.

Step 10. Decorate and Serve

Decorate the top of the cake with walnut halves for a classic look. Slice and enjoy with a hot cup of coffee or tea!