Thumbprint cookies

These easy cookies with a fruity jam filling are perfect teatime treats. Make a batch as a weekend project and fill up your biscuit tin.

For the shortcrust pastry, sift the flour and powdered sugar into a mixing bowl. Add the vanilla sugar, lemon zest and a pinch of salt. Rub the butter into the flour mixture until it is incorporated and then mix in the egg yolks. Knead everything into a compact smooth dough. Wrap the dough and put it in the refrigerator for 1 hr.
Remove the dough from the refrigerator and bring it to room temperature for 10 mins. Form the dough into a long roll and divide it into 60 equal portions. Form a small ball from each portion and place it on a baking sheet covered with baking parchment paper (you will need two or more sheets). Press a dip (for the jam) into each ball with the handle of a wooden spoon.
Heat the oven to 400F/gas 6. Heat the jelly in a saucepan over a low heat until it melts. Use a teaspoon to fill the dips in the dough balls with jelly.
Bake for 12-15 minutes, then allow to cool completely. Dust the cookies with some powdered sugar before serving. The cookies can be stored in an airtight container for several weeks.