Chestnut chocolate cookies

Makes about 15-20 large cookies

• 125g unsalted butter
• 250g sweetened chestnut purée
• 125g dark chocolate
• 75g icing sugar
• 2 egg yolks
• 225g plain flour

Step 1
I use a large piping bag with a star nozzle to make the cookies, creating a snake-like swirl with pointed grooves trailing through it, but you can just use a spoon to spread the mixture on to the tray in ovals or rounds.

Step 2
Line two baking trays with foil – scrunch it tight around the edges, so it will keep steady when you pipe on the biscuits – and heat the oven to 170C (150C fan-assisted)/335F/gas mark 3.

Step 3
Beat the butter until light and creamy, then stir in the chestnuts, chocolate, icing sugar and yolks.

Step 4
Sift and stir in the flour, then take a large piping bag with a star nozzle and pipe 5cm wide x 10cm long zigzags of the mixture on to the tray.

Step 5
Bake for 35 minutes, or until crisp.

Step 6
Store in an airtight container.