100g butter, plus some for greasing
2 tbsp golden syrup
200g caster sugar
200g dark chocolate
2 tsp vanilla extract
100g plain flour
2 eggs
Line an 8inch square tin with baking paper. Melt a little bit of butter and paint it into the tin. Preheat the oven to gas 4.
Put 9 biscuits in a single layer on a plate. Microwave for 20 seconds, then split open with a butter knife. Arrange pattern side down in the tin, 3 rows of 6.
Chop up the remaining biscuits. Stir the chocolate mixture to make sure it is all melted and incorporated. Beat the eggs into the chocolate.
Bake for 25 minutes, turning half way through. Take out when they have risen and firmed slightly. Leave to cool in the tin. When cold, lift out of the tin and turn over. Cut into bourbon sized rectangles along the bourbon top.