Jam Thumbprint Cookies

On the work surface, quickly knead together flour, cold butter in pieces, powdered sugar, egg yolks and finely grated lemon zest into a smooth dough.

Wrap the dough in cling film and chill in the refrigerator for about 60 minutes.

Preheat the oven to 160 °C (fan) and line a baking sheet with parchment paper.

With floured hands, form hazelnut-sized balls, place them on the sheet, and press a depression into the center of each ball with the handle of a wooden spoon.

Bake the cookies for about 15 minutes.

Remove the thumbprints from the sheet and let them cool completely on a wire rack.

Briefly warm the jam, stir until smooth, and spoon a dollop into each indentation.

Let the jam set, then serve or store in a cookie tin.