How to make
Melt the butter and chocolate together in a water bath.
In a bowl, beat the eggs with the white and brown sugar. Add the vanilla essence.
Finely chop the walnuts.
Combine the egg and chocolate mixture. Add the flour and walnuts. Stir.
Spread the mixture in a rectangular baking pan, which is covered with a sheet of baking paper.
Bake the brownie in a preheated oven at 360°F (180 C) for 30-35 minutes.