To start baking this delicious treat, preheat your oven to 180C/160C fan and prepare two 18cm sandwich tins by lining and buttering them. Next, grab a bowl and combine the sugar and butter, whisking until the mixture is incredibly fluffy and has a pale appearance.
Take a mug and whisk the eggs using a fork. Gradually add the eggs to the mixture, including 1 tablespoon of flour each time, making sure not to use all of the flour at once. Once the eggs are fully combined, gently fold in the rest of the flour.
Add the dissolved coffee to the mixture while still gently folding it in. Then, divide the mixture into the sandwich tins and cook for 25-30 minutes or until the cake has risen and is firm, and a skewer inserted into the middle comes out clean. Let the cake cool in the tin for five minutes before transferring it onto a wire rack to cool completely. If desired, you can freeze the cake at this point.
Meanwhile, create the icing by beating the icing sugar and butter until the mixture is light and fluffy. Then, add the dissolved coffee and continue to whisk. Cover the icing and set it aside until it's ready to be used on the cake.
To assemble the cake, spread half of the icing on the bottom of one sponge and then spread the strawberry jam on the bottom of the other sponge (if using). Sandwich the two sponges together, and then spread the remaining icing on top. For a decorative touch, add walnuts or cherries on top. Enjoy!
