Step 1

Preheat the oven to 180ºC, 350º F, gas mark Grease and line a 20cm (8in) square baking tin.

Step 2

Melt the butter with 55g (2oz) of the chocolate in a heatproof bowl over a pan of hot water.

Step 3

Beat the eggs with the sugar in a large bowl, then sift in the flour, and baking powder. Stir in the melted chocolate mixture, and beat together until well blended.

Step 4

Chop the remaining chocolate into rough chunks and stir into the brownie mixture, with the walnuts. Spoon into the tin and spread evenly.

Step 5

Beat the caramel in a small bowl and swirl into the mix. Bake for about 30 mins, the cake should begin to shrink slightly from the sides of the tin.

Step 6

When cool cut the brownie cake into squares.