In large nonstick skillet, heat oil over medium heat, cook onion and mushrooms for 5 minutes or until tender, stirring often. Add garlic, parsley, basil, oregano, hot pepper flakes, tomato paste and tomatoes; simmer, uncovered, for 10 minutes. Add sweet peppers; simmer for 10 minutes or until sauce is thickened. Season with salt and pepper to taste.
Filling: combine cottage cheese, half of the Parmesan and the oregano; mix well.
Assembly: in 13x9 inch baking dish, spread 1 cup tomato sauce over bottom. Top with layer of noodles. Cover with half of the cottage cheese mixture, then one-third of the mozzarella cheese and one-third of the remaining sauce. Add another layer of noodles; spread with remaining cottage cheese mixture. Layer with half of the remaining mozzarella, then half of the sauce and final layer of noodles. Top with remaining sauce and mozzarella, then Parmesan. (Lasagna can be prepared to this point, covered and refrigerated for up to 1 day. Add 15 minutes to baking time).
Bake, covered, in 350F oven for 45 minutes to 1 hour. Uncover and bake for 10-15 minutes longer or until hot and bubbly. Remove from oven and let cool for 5 minutes before serving.