Line a baking sheet with parchment paper and put in the oven. Preheat the oven (top / bottom heat: 200 ° C, fan: 175 ° C, gas: level 3) Mix the flour, eggs, milk, salt and pepper together until smooth. Stir in the mineral water.
Peel the onions and finely dice them. Heat the oil in a large pan. Fry the minced meat in it, turning. Add the onions and fry briefly. Season with salt, pepper and paprika.
Take the baking sheet out of the hot oven and immediately pour the batter on top. Pre-bake 3 - 4 minutes. Wash and slice the tomatoes and remove the pancake from the oven.
Cover the pancake with the tomatoes and sprinkle with herbs. First spread the minced meat, then the cheese and bake for about 15 minutes. Remove, garnish with basil and cut open.