Grease or spray 2 8" cake pans. Line the bottom with parchment paper, grease, and dust the entire pans with flour.

Preheat the oven to 350F (180C)

Using a stand mixer, hand mixer or by hand, cream the butter and sugar until light and fluffy. Add an egg to the butter and sugar mixture and blend thoroughly.

Add about a quarter of the flour and mix until cleared. Repeat with the remaining eggs and flour until the eggs and flour are used.

The cake mixture will be light and creamy.

Add the chopped nuts. Stir the espresso powder into the liquid espresso, then add to the mixture.

Blend well, then divide the cake mixture into the prepared 8" cake tins.

Bake for about 30 minutes or until a cake tester comes out clean. Cake will be a lovely golden brown color.

Allow the cakes to cool in the pans for 10 minutes, then carefully remove and place on cooling racks (remove the paper.)

Blend all the ingredients for the buttercream together until you have a smooth and creamy frosting. 

If the cakes aren't flat on top, cut them so that they are level (I like to use this super inexpensive tool.) Then either spread or pipe just under half of the frosting on one layer of the cake (the cut side.)

Place the second layer on top. Be sure to put the cut side down (so both cut sides are facing each other in the middle.) Spread the frosting on the top. This is a very rustic cake, so don't worry if you don't get it to look perfect.

Next, pipe rosettes on top of the cake (or you can place dollops of frosting) for 8, 10 or 12 walnut halves to sit on, depending on how many slices you want to have.

Lastly, add a walnut half to each rosette. That's it! You've just made a classic British coffee and walnut cake!