Scrumptious Vegetable Lasagna

Ingredients

• 9 whole wheat lasagna noodles
• 2 medium yellow summer squash, cut into 1/4-inch slices
• 2 medium zucchini, cut into 1/4-inch slices
• 1 large green pepper, chopped
• 1/2 pound sliced fresh mushrooms
• 1 large sweet onion, chopped
• 1 tablespoon olive oil
• 1 jar (25 ounces) marinara sauce
• 1 carton (15 ounces) fat-free ricotta cheese
• 9 slices reduced-fat provolone cheese, halved
• 2 cups shredded part-skim mozzarella cheese
• 1 cup grated Parmesan cheese