Heat the oven to 180C/160C fan/gas 4 and line two baking trays with baking parchment. Combine the sugar and nut butter. Crack in the egg and whisk again until smooth and creamy. Roll into 18 balls and arrange on the prepared tray, well spaced apart.

Press down twice on each cookie in a criss-cross pattern using the back of a fork until flat and round. Sprinkle over the chopped nuts, if using. Bake for 10-12 mins until golden brown. Leave to cool on the tray for 10 mins before removing to a wire rack to cool completely. Once completely cool, you can dip them in melted chocolate and leave to set before serving. Will keep in an airtight container for two days.