Make this with any coffee you like, from instant granules to freshly ground Yirgacheffe beans - but make it strong or the coffee flavour will be too faint.
150g castor sugar
150g butter, softened
Pinch of salt
3 large eggs
125g sour cream
2 tbsp very strong black coffee
½ tsp vanilla extract
170g self-raising flour
1 tsp baking powder
2 tbsp milk
50g walnuts, chopped
50g granulated sugar
1 tbsp plain flour
1 tsp cinnamon
Heat the oven to 180C. Beat the sugar, butter and salt together until pale.
Add the eggs one at a time, beating well, then the sour cream, coffee, and vanilla. Fold in the sifted flour and baking powder, then lightly mix in the milk.
Transfer to a buttered, deep-sided 20 cm round or square cake tin.
Mix the topping ingredients together, and scatter generously on top. Bake for 40 to 45 minutes or until an inserted skewer comes out clean.
Serve warm or at room temperature, with coffee.