Source: Lorraine Pascale
150g butter or margarine
200g chocolate *dark or a mix of dark and milk, as preferred) broken into chunks
250g digestive biscuits (Americans, you can sub graham crackers!)
200g soft light brown sugar
300g crunchy peanut butter
1 tsp. vanilla extract or vanilla bean paste
Line a 20cm square cake tin with baking parchment, leaving some excess paper draping over the edges to assist in removing from the tin after baking.
Melt the butter in a large pan over low heat, then set aside.
Put the chocolate in a small bowl and either melt in the microwave in 30 second bursts, stirring well after each session, or melt over simmering water, stirring continuously. (Make sure the chocolate doesn’t touch the water or it will become grainy!)
Whizz the digestive biscuits and brown sugar in a food processor until they become fine crumbs. Tip into a bowl and pour in the melted butter. Add the peanut butter and vanilla and mix until well combined.
Tip the mixture into the lined tin and press down firmly with the back of a spoon. The mix needs to be finely compacted and tight. Then pour over the melted chocolate, tilting the tin back and forth a bit so that the whole mixture is evenly coated. Put into the freezer for about 30 minutes to firm up.
Once the chocolate is set, remove the pan from the freezer, Lift the paper out and place on a cutting board or firm surface. Using a sharp knife, cut into 16 squares. These will keep for a few days in an airtight container, or in the freezer for longer.