Knead the wholemeal flour with quark, butter and salt to form a smooth dough. Wrap the dough in foil and let it rest for an hour in the refrigerator.
In the meantime, peel the mushrooms, cut them into slices and fry them in a large non-stick pan with a little butter, lightly salt and pepper and let cool. Chop the onion and fry it with a little butter. Cut the zucchini into slices and fry them in a large non-stick pan with a little olive oil, season with salt and pepper and leave to cool. Cut the tomatoes into slices.
Preheat the oven to 180 ° C. Grease a round tart pan or springform pan with a little butter and sprinkle with breadcrumbs.
Roll out the dough on a floured work surface and place it in the prepared pan, forming a 2 cm high edge. Prick the dough several times with a fork. Then bake blind for 12 minutes on the lowest rack.
Sprinkle the pre-baked dough with approx. 1 tablespoon of breadcrumbs. Spread the zucchini slices evenly on top. Season lightly with pepper, salt and herbs. Then distribute the mushrooms evenly on top and season again lightly. Then distribute the tomato slices evenly on top and season again lightly. Finally, distribute the fried onions on the tomatoes.
Whisk the cream, crème fraîche and eggs together and season with salt and pepper. Spread the cream and egg mixture evenly over the tart. Finally, grate the cheese and sprinkle evenly over it.
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