Heat a large, nonstick skillet over medium heat. Add ground beef and cook, breaking up chunks, until meat is no longer pink. Stir in marinara sauce. Spread 1 cup meat sauce in 13-x-9-inch baking dish; place three noodles crosswise on sauce (don’t overlap noodles). Scrape ricotta into a bowl; add egg and stir until blended. By spoonfuls, drop /3 of the ricotta mixture and /3 of the pesto over the noodles; top with /3 of the peppers, cup mozzarella, and three more noodles. Spread 1 cup meat sauce over top to cover the noodles and repeat layers twice, starting with ricotta and pesto. Sprinkle with remaining mozzarella. Cover with plastic wrap, then foil, and refrigerate up to one day.
To bake, heat oven to 375º. Remove foil and plastic wrap; re-cover with foil. Bake for 50 minutes or until edges bubble and center is hot.