Heat oven to 350°F. In extra-large non-stick skillet over medium heat, cook sausage; add vegetables and garlic powder. Cook, stirring frequently, until vegetables are crisp tender. Meanwhile, cook pasta according to package directions; drain. In 13 x 9-inch baking dish, stir together ricotta cheese and spaghetti sauce until well blended. Stir in mozzarella cheese, hot pasta and vegetable mixture; season to taste. Cover; bake 20 to 30 minutes or until hot and bubbly. 9 servings (1 cup each).