Sausage and Zucchini Lasagna

INGREDIENTS

• 1/4 cup spaghetti sauce
• 1 tablespoon vegetable oil
• 1 pound bulk pork sausage
• 2 zucchini, quartered and sliced
• 1 pound ricotta cheese
• 1 egg white
• 8 ounces shredded mozzarella cheese
• 1/4 cup grated Parmesan cheese
• 6 no-boil lasagna noodles, or more if needed
• 2 cups spaghetti sauce, divided
• 1/2 cup grated Parmesan cheese