- Place 2 types of flour, powdered sugar, vanilla sugar and lemon zest in a mixer bowl, and mix everything well with a paddle attachment.
- Cut the cold butter into cubes, and add it to the flour mass. Knead until wet crumbs.
- Add a cold egg, and mix for a couple of seconds. As soon as the dough starts gathering into a ball, stop kneading.
- Wrap the dough in cling film, and put it in the fridge for a couple of hours.
- Combine the lemon juice, sugar, yolk and zest, mix well until smooth, and put on a small heat.
- Boil until thick, stirring constantly.
- Strain the finished hot curd.
- Let the curd cool a little, and add the butter.
- Cover the mass with cling film in contact, and put it in the fridge to stabilize.
- Remove the dough from fridge, and roll it out between two sheets of parchment.
- Cut out the cookies. Use an egg cutter. Make holes in half of the cookies using the back of a pastry nozzle.
- Bake the cookies at 320F (160C) for 12 minutes.
- The cookies should be light (the main thing is not to overdry it). Always focus on your oven.
- Let the baked blanks cool.
- Spread a thin layer of curd on the whole half of the cookies, and cover with the other half (with a hole).
- If you want to sprinkle the cookies with powdered sugar, then immediately powder half of the cookie with a hole, and then just glue two halves together.