Mix the flour, yeast and salt, add olive oil and water and knead everything very thoroughly for about 10 minutes until a soft, elastic dough is formed.
Put the dough in a bowl and let rise, covered, for approx. 1 - 1.5 hours until it has doubled in volume.
Chop off the dough and let it rest for 10 minutes.
Roll out the dough into a circle approx. 25 cm in diameter, place on a baking sheet and let rise covered for approx. 30 minutes until it has doubled its volume again.
Use a tablespoon or your fingertips to make 1 cm deep dents in the surface of the dough. Spread the Gruyère, onions, thyme, salt and pepper evenly on top, drizzle with oil and bake in the oven preheated to 200 ° C for about 30 minutes.