To loosen the butter to middle fire in a frying pan with the heavy fund. To add the onion, the garlic and to cook for 3 minutes mixing. To put in the frying pan the snails, uice of lemon, thyme, salt and pepper and to cook for 3 minutes mixing. To add the parsley and to remove from the fire. To put the snails in a dish in refrigerator, to unite kitchen whipped cream to the fund of cooking in the frying pan and to put aside. To cut pasta in two pieces; tender aside a piece wound in the transparent film and to stretch the other to a thickness of 1 mms. To cut the puff pastry, with the edge of a glass, in 12 circles. To put half snail a little down of the center of the circle and to manufacture the tortellinis as above. To continue to exhaustion of the pasta. To cook the tortellini in 3 liters water in ebullition with 1 1/2 teaspoon of salt up to when they come floating (4-5 minutes). Drain the tortellini, to put them in the frying pan with the well warm sauce, to mix and to serve immediately.