Leeks are washed and cut into rings. In a pan put olive oil, then add the onion, finely chopped, mix well and add the leeks. Stir and leave to fry for 2-3 minutes on low heat. After the mixture was fried is removed from the heat and set aside. In a large bowl whisk the eggs and add the cream. The mixture is stirred gently and very well, then add salt and sprinkle with pepper. Gruerat was added to the mixture and stirred. In another pan fry the grated bacon, but without added fat. Puff dough is placed in a round pan on baking paper. On dough arrange the onions, leeks and bacon. Pour the mixture of eggs, cream and gruera. The oven was heated to 180 C, 15 minutes before baking. Bake for half an hour from time to time, the tray is rotated. Serve warm.