Onions peel, halve and cut into thin slices. Heat the oil in a pot. Fry the onions for about 10 minutes, stirring occasionally. Add honey, wine vinegar and 5 tbsp. water and cook covered for about 10 minutes, stirring occasionally.
Remove onions from the stove and let them cool lukewarm.
Pluck the mozzarella into pieces. Wash the thyme, shake dry and chop the leaves of 4 stems coarsely. Roll out the dough and place on a baking tray. Season onions with salt and pepper and spread on the dough, spread mozzarella evenly on top.
Bake the tarte flambée on the lower shelf in a preheated oven (electric oven: 225 °C/ convection oven: 200 °C/ gas: see manufacturer) for 15-20 minutes.
Wash, clean and halve or slice the strawberries. Mix strawberries, pepper, chopped thyme and balsamic vinegar. Slice parmesan cheese into shavings. Take the tarte flambée out of the oven
Spread strawberries on top, sprinkle with parmesan and remaining thyme and serve immediately.