Cook lasagna noodles according to package directions, drain carefully. Preheat oven to 350 degrees F.
In a large bowl, combine ricotta and parmesan cheeses, eggs, salt and pepper.
Spread ½ cup marinara sauce on the bottom of a 13×9 baking dish. Cover with pasta, overlapping edges slightly.
Spread ½ cheese mixture over the pasta. Top with another layer of pasta. Repeat with 1 ½ cups sauce, then pasta and cheese mixture. One more layer of pasta and then remaining sauce and then shredded mozzarella cheese. Sprinkle with red pepper flakes if using.
Cover loosely with tin foil and bake 45 minutes until bubbly. Remove foil and bake an additional five minutes until top is browned.
Let stand for about 15 minutes to set.