In a food processor whizz together the flour, sugar, ground almonds and butter till they resemble fine crumbs.
Add the egg yolks and process until all is combined.
Form a ball, cover it in cling film and let it rest in a fridge for at least 30 minutes.
Preheat an oven to 160 degrees Celsius.
Roll out the dough pretty thinly (approx. 5 mm) on a floured surface, cut out 5-6 cm diameter circles and in half of the biscuits cut out a small circle in the middle.
Transfer the biscuits onto the baking tray covered with baking paper leaving some space between them (they will not rise a lot). The dough is not very elastic so be careful when you transfer the cut out biscuits as they may break.
Bake the biscuits for approx. 15 minutes until golden; let them cool down on a baking tray.
When cold, spread some jam on a whole biscuit, cover it with a biscuit with a hole in the middle, sprinkle with icing sugar.