Step 1

Grease and line 2 baking sheets. Melt the butter and set aside to cool.

Step 2

Combine flour, bicarbonate of soda, vanilla and 1/4 tsp sea salt in a bowl and set side.

Step 3

Combine the sugars with the cooled, melted butter and stir until no lumps remain. Combine the egg, egg yolk and milk and mix with the sugar and butter until thoroughly combined.

Step 4

Add the flour, mixing until everything is incorporated.

Step 5

Add the Daim and mix to combine. Wrap the dough in clingfilm and chill for a few hours.

Step 6

Preheat the oven to 190°C/170C/ gas mark 5/375F.

Step 7

Form the dough into 18-20 balls.

Step 8

Place on the prepared baking sheets around 5 cm/2 inches apart. Bake for 8–10 minutes - or until just golden.

Step 9

Remove from the oven immediately and transfer to a cooling rack – the middle should still be slightly soft but they will harden up after a while.