Vanilla shortbread dough

Tip the flour into a food processor. Cut the butter into small pieces and drop them into the bowl, then whizz until the mixture looks like breadcrumbs.

Add the sugar, vanilla and egg yolks and whizz to a small dough.

Tip the dough onto a sheet of non-stick baking parchment and use the paper to roll the dough into a log shape, twisting the ends like a cracker. Chill for 3 hours or overnight.

Heat oven to 180C/160C fan. Slice the log into 1cm-thick rounds and arrange on a baking sheet leaving gaps between them.

Bake for 15-20 mins until golden. Leave to firm on baking sheet for 3-4 mins then transfer to a wire rack.