Cook pasta according to package directions. Meanwhile, in large pot, saute Italian sausage, ground beef, garlic, and onions. When meat is cooked, drain off excess fat. Add spaghetti sauce, salt and pepper. Bring meat sauce to a boil, reduce heat and simmer for 15 minutes.
In a large mixing bowl, combine ricotta, mozzarella and parmesan cheeses with beaten egg, mix until smooth.
Pre-heat oven to 350°F. Grease a 9x13 baking dish. To build lasagna, start with a layer of lasagna noodles, then 1/3 of the cheese mix, then 1/3 of the meat. Repeat layering process (noodles, cheese, meat) and once again with meat being the final layer. Top with some Parmesan cheese. Bake COVERED for 25 minutes and uncovered for 25 minutes. Let stand 10 - 20 minutes before slicing and serving.