Finely pound the fennel seeds in a mortar or grind them finely in a blender. Mix the flour, sugar, salt and fennel seeds in a bowl. Pour in the olive oil and knead into a dough. The dough is very crumbly.
Preheat the oven to 180 ° C (top / bottom heat, circulating air is not suitable). Roll out the dough about 1 cm thick and cut out 5 cm circles. Place on a baking sheet lined with baking paper. Bake in the middle of the oven for about 15-18 minutes.
Take out of the oven and generously sprinkle with icing sugar while it is still hot, allow to cool on the baking tray.