Greek Salad Lasagna

LASAGNA

• 2 (6-oz. each) yellow bell peppers
• 2 (6-oz. each red bell peppers
• 1 tablespoon olive oil
• 1 pound chopped frozen spinach, thawed
• 2 cups cups (about 10 oz.) chopped pitted olives
• 3 tablespoons chopped fresh oregano
• 1 1/2 teaspoons kosher salt
• 1/2 teaspoon crushed red pepper
• 16 uncooked lasagna noodles
• 3 1/2 cups marinara sauce (from 1 [32-oz.] jar)
• 10 ounces feta cheese, crumbled (about 2 1/2 cups)
• 10 ounces pre-shredded low-moisture part-skim mozzarella cheese (about 2 1/2 cups)
• 1 1/2 cups ricotta cheese