Coffee & walnut cake

Ingredients
200g softened unsalted butter, chopped
1/2 firmly packed cup (125g) brown sugar
1/2 cup (110g) caster sugar
3 eggs
1 1/3 cups (200g) plain flour, sifted
1/2 teaspoon baking powder
50ml milk
1 cup (120g) chopped walnuts, plus extra to serves
90ml coffee essence (see notes)
1 1/3 cups (200g) icing sugar, sifted

Coffee buttercream
120g softened unsalted butter, chopped
2 2/3 cups (250g) icing sugar
2 tablespoons coffee essence (see notes)


Method
Step 1 
Preheat the oven to 180°C. Grease and line a 23cm x 12cm x 7cm loaf pan.
Step 2 
Beat butter, brown sugar and caster sugar with electric beaters until thick and pale. Add the eggs, 1 at a time, beating well after each addition. Fold in the flour and baking powder, followed by the milk, walnuts and 50ml coffee essence. Spoon into the pan and bake for 35-40 minutes until a skewer inserted into the centre comes out clean. Cool slightly, then turn out onto a wire rack to cool completely.
Step 3 
For the buttercream, beat the butter, icing sugar and coffee essence with electric beaters until thick and pale.
Step 4 
Slice the cake horizontally into 3 layers. Place bottom layer on a serving plate and spread with half the buttercream. Top with another layer and remaining buttercream, then place remaining cake layer on top.
Step 5 
To make the icing, place icing sugar and remaining 2 tablespoons coffee essence in a bowl and stir until smooth. Pour over the cake, allowing it to drip down the sides. Garnish with extra nuts, then serve.