Cook noodles according to package directions. Meanwhile, in a large skillet, cook beef over medium heat until no longer pink; drain. Stir in taco seasoning and one jar of salsa or picante sauce. Add chili powder and cayenne pepper if using. In a small bowl, combine the egg and ricotta cheese. Drain noodles.
In a 13-in. x 9-in. x 2-in. baking dish, spoon enough beef to cover. Then add a layer of three noodles, half of the ricotta mixture, half of the beef mixture, half of cheese and repeat. (Reserve half cup of cheese). Then, add noodles and the other jar of salsa or picante sauce to cover. Bake the casserole, uncovered, for 30 minutes or until heated through. Add reserved cheese on top and bake for 10 more minutes. Let stand for 10 minutes before cutting.