In a skillet, cook the ground beef and Italian sausage over medium heat until browned. Add diced onions and minced garlic, and cook until onions are translucent. Stir in tomato sauce, diced tomatoes, Italian seasoning, salt, and pepper. Simmer for 10 minutes.

Preheat the oven to 375°F. In a mixing bowl, combine ricotta cheese, mozzarella cheese, and Parmesan cheese. Spread a layer of meat sauce on the bottom of a baking sheet. Place a layer of lasagna noodles on top, followed by a layer of cheese mixture. Repeat layers until all ingredients are used up.

Cover the baking sheet with foil and bake in the preheated oven for 25 minutes. Remove the foil and bake for an additional 10 minutes until the cheese is bubbly and golden brown.

Let the lasagna cool for a few minutes before slicing and serving. Enjoy!