Chop the onion and sauté in a little olive oil until translucent. Add the tomatoes, season with salt and pepper and simmer for about 10 minutes.
Meanwhile, wash the zucchini (as small as possible), cut into slices and fry in plenty of olive oil. Season with salt, pepper and oregano. Line a springform pan or quiche form with a diameter of 26 cm with the puff pastry.
Mix the eggs, crumble the sheep`s cheese and mix both with the tomato sauce. Fold the zucchini into the mixture and pour everything into the pan. Bake for 20 minutes at 200 ° C, then turn the oven down to 180 ° C and bake for another 20 minutes.