Ingredients

Step by step

1. Chop the chocolate into small chunks then melt half in a heatproof bowl set over a pan of just-simmering water; leave to cool.
2. In a large mixing bowl, cream the butter and sugar together for at least 2 minutes until pale and fluffy. Beat in the egg, soured cream and melted chocolate.
3. Combine the flour, oats and bicarbonate of soda in a separate bowl, then fold into the chocolate mixture along with the chopped chocolate and peanuts. For crisp cookies, shape and bake straightaway while the mixture is soft; if you want a chewier texture then chill the mixture until firm. Preheat the oven to 180°C, fan 160°C, gas 4, and line 2 or 3 baking trays.
4. Scoop out the mixture and roll into balls, spacing them out on the trays to allow room for spreading. Press a few extra peanuts onto each ball.
5. Bake for 15-17 minutes, then give the trays a sharp rap on the countertop to flatten the cookies out. Cool on the trays for about 10 minutes to firm up, then transfer to a cooling rack. Store in an airtight container; they will keep for at least 1 week.