Step 1

Finely crush biscuits in a food processor. Melt 75g butter and combine with biscuits. Press into the base and sides of a 24cm loose-bottomed tart pan and chill for 30 minutes until firm.

Step 2

Combine peanut butter and icing sugar in a bowl and spread in the tart base.

Step 3

Place chocolate and remaining 100g butter in a clean bowl over a pan of simmering water (don’t let the bowl touch the water). Stir until melted, then cool slightly. Spread over the peanut butter layer and chill for 30 minutes until firm.