For the fennel grissini, dissolve the yeast with the sugar and 3 tablespoons of flour in a little lukewarm water. Cover this dampfl and let it rise for 15 minutes. Knead with the remaining ingredients to a smooth dough. Cover and let rise for about 40 minutes.
Roll out the dough on a floured work surface to a rectangle about ½ cm thick. Cut into strips about 30 cm long and ½ cm thick and roll into sticks with both hands.
Line a baking tray or 2 baking trays with baking paper and place the dough sticks on them, spacing them slightly apart. Brush with olive oil and sprinkle with the fennel seeds and sea salt.
Bake the fennel grissini in the preheated oven at 200 °C for about 15 minutes until golden brown.