Prepare a large rimmed baking sheet with parchment paper or aluminum foil.
Cook lasagna noodles according to package directions.
In a large (12 inch) skillet over medium-high heat, cook beef, sausage, and onion, crumbling the meat as it cooks until it is no longer pink. Drain well. Return the meat mixture to the skillet and stir in 2 cups spaghetti sauce. Reduce the heat to low and continue cooking for about 10 minutes.
Meanwhile, mix together the ricotta cheese, Italian seasoning, and egg.
Spread each noodle with the ricotta mixture, leaving about 1 inch uncoated, and then spread a layer of meat sauce over the cheese.
Roll up the lasagna noodle towards the uncoated end.