Peel the shallots and cut them into slices lengthwise. Wash the rosemary, shake dry and remove the needles. Wash and drain the tomatoes. Remove the puff pastry from the package.
Heat 2 tablespoons of oil in a tarte tatin pan. Add shallots, rosemary and tomatoes. Fry briefly over a high heat. Sprinkle with sugar. Fry over medium heat for about 12 minutes. Season with salt, pepper and vinegar.
Pull the pan off the hob (if there are more than 2-3 tbsp. of liquid in the pan, hold the pan at a slight angle and skim with a tablespoon). Spread the tomatoes in the pan. Preheat the oven (electric cooker: 200 °C/circulating air: 175 °C/gas: see
Remove the dough from the paper. Place on the cherry tomatoes. Carefully press down the excess dough between the tomatoes and the inside edge of the tin.
Bake the tart in a hot oven for 18-20 minutes. Drain the mozzarella. Take the tart out of the oven and let it rest for about 5 minutes. Carefully fall onto a plate (caution, danger of splashing!). Pull the mozzarella apart.
Serve on the tarte. Sprinkle with 1 tablespoon of oil.