Preheat oven to 375°F Heat oil in large skillet. Sauté onion for 2 minutes, then add turkey and cook an additional 5 to 7 minutes.
Add tomato sauce, all seasonings, garlic, and mushrooms and simmer 2 minutes. Remove pan from heat.
In a bowl, combine spinach, ricotta, and nutmeg. Bring a large pot of salted water to boil. Cook pasta according to package directions until al dente. Drain and rinse with cool water.
Coat a 9" x 13" baking pan with cooking spray. Arrange 1/3 lasagna noodles (3 noodles) on the bottom of the pan. Spread a layer of ricotta mixture, then turkey mixture, then 1/3 mozzarella. Repeat layers, ending with mozzarella.
Bake 20 to 25 minutes or until cheese bubbles. Cool at least 5 minutes before cutting.