8g instant espresso powder (6 tsp), dissolved in 115 mls (½ cup) hot water
For The Coffee Buttercream Frosting:
500g icing sugar
225g soft butter
5g instant espresso powder, added dry
5g more instant espresso powder, dissolved in 15 mls (1 Tblsp) boiling water
15mls (1 Tblsp) full-fat milk or cream
1. This can be made as 3 loaves, 2 dozen cupcakes, or as a two-layer cake.
2. Preheat oven to 160°C. Grease two 8-inch cake pans and line the base of each with baking parchment. Set aside.
3. To make the sponge, put the walnut pieces and sugar into a food processor and blitz until finely chopped together. Add this to the soft butter and whip until creamy in a stand-up mixer or with an electric hand mixer. Next add the eggs and whip again until fluffy.
4.In a separate medium bowl, combine the flour, baking powder, bread soda and salt. Add these combined ingredients to the walnut mixture.
5. Lastly, add the buttermilk and hot coffee. Starting on low speed, slowly combine the liquids with the rest of the batter. As the mix gets blended, gradually increase the speed. Make sure the bowl is completely scraped on the bottom and sides and mix until fluffy. This will be a relatively thin batter and will firm up if chilled in the fridge.
6. Divide the mixture between the 2 lined tins and bake in the oven for 55 minutes.
7. For loaves, bake 45 minutes. For cupcakes, bake 25 minutes.
8. To make the frosting, whip together the butter and icing sugar until creamy. Add the dry espresso, the hot coffee and the milk. Whip again until fluffy, being sure to scrape the sides of the bowl.
9. Decorate your cake with coffee buttercream frosting and walnuts.