Mix eggs, mineral water, 200 g flour, baking powder and 1/2 teaspoon salt to a smooth dough and let it rest for a while. In the meantime clean and wash the vegetables. Divide broccoli into small florets, cut stems into slices.
Cover both in 400 ml boiling salted water and steam for about 7 minutes, drain and collect the stock. Halve the mushrooms and cut the tomatoes into pieces. Heat the fat in a saucepan. Fry the mushrooms for about 5 minutes, turning them over.
Season with salt and cayenne pepper. Dust the rest of the flour over it. Add broccoli stock while stirring and bring to the boil. Warm up prepared vegetables in it. Season again and refine with crème fraîche.
Fry 8 pancakes one after the other in hot oil until golden brown on both sides. Roast the sesame seeds in a dry pan and arrange the pancakes on plates with the filling and sesame seeds sprinkled on top.