Preheat the oven to 180°C/gas mark 4. Line a baking sheet with baking paper. Using an electric mixer, beat the butter and sugars until fluffy. Stir in the flour and milk until combined. Add the remaining ingredients, mixing well. Bring it all together with your hands to form a dough.
Divide the mixture into 20 small balls. Flatten slightly, then place on the baking sheet. Bake for 15-20 minutes until golden. Cool slightly before transferring to a wire rack.