The deep-frozen puff pastry is folded and rolled out 4 times, folded and roll out 2 times more; the second time, roll to 1/4-inch thick. Use a round biscuit cutter to cut into 2-inch discs. Arrange them one at a time on a lightly moistened baking sheet. Leave them to stick and rest for 30 minutes in a refrigerator. Glaze with the egg, not allowing to dribble on the sides. Use a 1 1/4-inch round cutter to trace the lid in the center without pressing too much. Bake in a hot oven (400F) for 15 to 20 minutes. Meanwhile, drain the snails, and halve. Prepare the butter by mixing it with the other ingredients, all finely chopped, the salt, pepper and a small pinch of Four spices. Open the lid traced in the shells using the tip of a sharp knife. Put half of the snails into the shells, cover with butter, using a small spoon. Bake in a slow oven (300F) for 7 to 8 minutes. Serve hot as an aperitif.
