In a large saucepan, heat the olive oil and saute for approx. 10 the onions, mushrooms, pepper and turkey. Once they absorb all their juices, remove the saucepan from the fire; salt and pepper to taste.
Preheat the oven at 180 °C and oil well a large 40x31cm baking pan. Lay one pastry sheet. In a large bowl, softly beat the eggs together with the creme fraiche. Add this mixture to the mushroom mix; add all the cheese and stir.
Pour the stuffing on top of the pastry sheet and cover with the second sheet.
Oil them well and carve the pie in square pieces. Bake the pie for approx. 40 min, until golden brown.