Defrost 5 puff pastry sheetsf. Sprinkle salt and pepper over 2 beef fillets and bake them and brown in the hot butter. Remove them from the pan and set aside. Bake in the remaining fat 100 grams sliced chestnut mushrooms, 1 finely chopped shallot and 4 slices bacon, cut in little pieces. Bake until the chestnut mushrooms have softened Bring to taste with tarragon. Put each steak on a puff pastry sheet. Put the mushroom mixture on there and add 1 tablespoon spinach (defrosted). Spread 1 slice bacon over it. Place the puff pastry packages in a baking dish and spread an whipped egg over it. Put the baking dish in the preheated oven at 170 degrees (fan) for approximately 30 minutes. Enjoy!