Beat butter, icing sugar and bourbon vanilla sugar in a large bowl until well combined using an electric mixer.
Add one egg white and the zest of a half lemon and beat until pale and fluffy.
Stir in the flour until just combined.
Wrap the dough in a plastic wrap and let it chill in the fridge for 2 hours.
Take the dough out of the fridge and let it sit at room temperature for about 30 minutes.
Meanwhile, prepare everything else. Line two baking sheets with baking paper. Clean your working surface very well and flour it well with all-purpose flour (don't be sparing, the more flour, the less your cookies will stick on your working surface). Preheat your oven to 200° C / 392° F (conventional).
Place your dough on the well-floured working surface and roll out about 3-5mm thick.
Use a round cookie cutter to cut out your shape and place them on the lined baking sheets.
Now, for the half of the shaped cookies, use the small cutters (hearts, round, stars) to cut out the middle of the cookies -> these will be your tops.
If you have the possibility, let them chill for 15 minutes in a cool place. I use my balcony for that, as my fridge is not that big that the baking sheets with the cookies fit inside.
Bake your cookies for about 8 minutes in the oven. They should be slightly brown when you take them out.
Place them on a rack and let them cool down.
Meanwhile, place the jam in a small bowl and stir it well with a fork or spoon to loosen it a bit.
Turn the bottom cookies and spread them with the jam (about a half teaspoon on each) and place the tops on them.
Leave to dry for about 30 minutes and sprinkle with icing sugar before serving.