Cook pasta shells in boiling water for 15 minutes. Rinse under cold water and set aside. The mushrooms, onions, zucchini, and peppers are diced. Saute them in olive oil. Season with 1 tsp ground nutmeg and 1 tbs grated parmesan. Cool and stir in the defrosted chopped spinach and one beaten egg to bind it. Blend in 6 tbs ricotta. Stuff into the shells. Pre heat oven to 350 degrees. In a large casserole dish arrange shells on a bed of spicy tomato sauce. Bake for 15 minutes. Remove top with shredded mozzarella cheese and bake 5 minutes more. Options: You can use 1 lb (14 pieces) manicotti instead of shells. If you can only get jumbo shell (34 to a lbs) fill with about a tbs per shell.