Tomato-Sausage Lasagna

INGREDIENTS

• 12 dried lasagna noodles (about 10 ounces), uncooked
• 2 teaspoons olive oil
• 1 large onion, chopped
• 4 garlic cloves, finely chopped
• 1 1/2 teaspoons dried Italian seasoning
• 1/4 teaspoon red-pepper flakes
• 1 pound sweet Italian sausage, casings removed
• 2 cans (28 ounces each) whole peeled tomatoes in puree
• Coarse salt and ground pepper
• 6 cups shredded shredded mozzarella cheese (about 1 1/2 pounds)
• 3/4 cup shredded Parmesan cheese (about 3 ounces)