Coffee & walnut cake - Good Food Middle East

Ingredients

• 250g pack softened butter, plus extra for the tins
• 100ml strong black coffee (made with 2 tbsp coffee granules), cooled
• 280g self-raising flour
• 250g golden caster sugar
• ½ tsp baking powder
• 4 eggs
• 1 tsp vanilla extract
• 85g walnuts, 2 tbsp roughly chopped, the rest finely chopped
• 100g icing sugar, sifted, plus a little extra for dusting
• 150ml double cream
• 100g mascarpone, at room temperature