Cook's tips: For brownies to be good they must not be overcooked. The secret is to take them out of the oven just before you think they are done – the middle should be soft and squidgy, not set firm.
Don't worry if there is a dip in the middle and a crack on top, this is how it should be, and you will find the mixture firms up on cooling.
* 375g plain chocolate, broken into pieces * 250g baking margarine
* 2 tsp instant coffee
* 2 tbsp hot water
* 2 eggs
* 250g caster sugar
* 1 tsp vanilla extract
* 90g self-raising flour
* 175g walnut pieces
* 250g plain chocolate chips
1. Grease a 30x23cm (12x9in) roasting tin, line the base with greaseproof paper, and grease the paper.
2. Put the chocolate and margarine in a bowl and sit the bowl on top of a small saucepan of gently simmering water. Melt the chocolate slowly, then remove the bowl from the pan and let the chocolate cool.
3. Put the coffee in another bowl, pour in the hot water, and stir to dissolve. Add the eggs, sugar, and vanilla extract. Gradually beat in the chocolate mixture. Fold in the flour and walnuts, then the chocolate chips.
4. Pour the mixture into the prepared tin and bake in a preheated oven at 190°C (170°C fan, Gas 5) for about 40–45 minutes or until firm to the touch. Don’t overcook – the crust should be dull and crisp, but the middle should still be gooey. Leave to cool in the tin, then cut into 24 pieces.
Recipe from Mary Berry's Complete Cookbook, DK, £25, www.dk.com.