1. Preheat the oven to 375°F (190°C) and lightly grease a half-sheet baking pan.

2. In a large skillet, brown the ground beef and sausage (if using) over medium heat. Drain excess fat.

3. Add chopped onion and garlic to the skillet and cook until fragrant, about 3–4 minutes.

4. Stir in crushed tomatoes or marinara, Italian seasoning, salt, and pepper. Simmer for 10–15 minutes.

5. In a bowl, mix ricotta cheese with egg, ¼ cup of the parmesan, and a pinch of salt.

6. Cook lasagna noodles in salted water until al dente. Drain and lay flat to avoid sticking.

7. Place a layer of noodles on the prepared pan. Spread meat sauce, then spoonfuls of ricotta mixture, then mozzarella.

8. Repeat layers until ingredients are used up, ending with sauce and remaining cheese on top.

9. Cover loosely with foil and bake for 20 minutes. Remove foil and bake an additional 10–15 minutes until bubbly and golden.

10. Let rest for 10 minutes before slicing and serving.