Coffee & Walnut Cake

Ingredients

• 4 large eggs
• 300g plain flour
• 100g sour cream
• ½ tsp fine salt
• 200g caster sugar
• 200g unsalted butter, softened
• 2 tsp baking powder
• 3 tbsp strong brewed coffee (espresso)
• 2 tbsp caster sugar
• 2 tbsp strong brewed coffee
• 2 tbsp milk (optional to loosen)
• 300g icing sugar, sifted
• 1 tsp vanilla extract
• 100g walnuts, toasted and chopped

Method

1. Heat the oven to 180°C (fan 160°C/gas 4). Grease two 20cm round tins and line the bases with baking paper. While the oven climbs, toast the walnuts on a dry tray for 6–8 minutes until they smell warm and nutty — keep an eye on them, they go from golden to bitter fast.
2. Beat the softened butter and caster sugar with electric beaters for 4–5 minutes until pale, fluffy and noticeably lighter in colour. This is where the cake gets its lift, so don't rush it — you're whipping air into the fat.
3. Add the eggs one at a time, beating well between each. If it looks like splitting, add a tablespoon of the flour to bring it back together.
4. Sift in the remaining flour, baking powder and the fine salt — that pinch of salt is what makes the coffee taste of coffee rather than just bitterness. Fold through gently until just smooth, then stir in the espresso and soured cream until the batter is glossy and drops slowly from the spoon. Taste a smear from the bowl: it should be sweet but with a savoury edge from the salt. Adjust now if it tastes flat.
5. Divide between the tins, level the tops with a palette knife and bake for 30–35 minutes until risen, deeply golden and springy to the touch — a skewer should come out with a few moist crumbs, not wet batter. Cool in the tins for 10 minutes, then turn out onto a wire rack.
6. For the drizzle, warm the coffee and sugar in a small pan for about a minute until the sugar dissolves into a thin syrup. Brush generously over both sponges while they're still warm so it soaks into the crumb rather than sitting on top.
7. For the buttercream, beat the softened butter on high for 3–4 minutes until very pale and almost white — under-beaten butter gives you a heavy, greasy icing. Add the sifted icing sugar in two additions, beating well between each, then beat in the vanilla, coffee and a tiny pinch of salt to stop the sweetness running away with you. Loosen with a splash of milk only if it feels too stiff to spread. Taste — it should be coffee-forward, not just sweet.
8. Sit the first sponge on a plate or stand, spread over a thick layer of buttercream and sandwich with the second. Swirl the rest over the top in generous waves, taking it right to the edges.
9. Press the toasted walnuts into the top and lightly around the sides, then finish with a cluster of walnut halves in the centre. Slice thickly with a hot, dry knife and serve.