Preheat oven to 160°C/320°F/Gas 3. Lightly grease an oblong brownie tin. 25cm/10" x 15cm/6". Small roasting tin would also do. Melt the butter/margarine and chocolate together over a low heat. Remove from heat, add the sugar and mix well. Add vanilla essence, eggs and chopped walnuts. Sieve the flour, salt and baking powder together and gently stir into chocolate mixture. Pour into prepared tin and bake for about 40-50 minutes until crusty on top. Remove from oven and allow to cool, cut into brownies.
175g/6oz Odlums Cream Plain Flour 225g/8oz Butter or Margarine (room temperature) 125g/4oz Chocolate (good quality, at least 60% cocoa) 325g/12oz Shamrock Golden Caster Sugar 2 teaspoons Goodall's Vanilla Essence 4 Eggs (beaten) 80g Shamrock Chopped Walnuts Pinch of Salt ½ teaspoon Baking Powder