In a large skillet, heat 2 tablespoons of olive oil over medium heat. Sauté 1 diced onion until translucent, about 5 minutes. Add 2 cloves of minced garlic and cook for another minute. Crumble in 1 pound of ground beef and 1 pound of Italian sausage; cook until browned, then drain excess fat. Stir in 28 ounces of crushed tomatoes and 2 tablespoons of tomato paste, allowing it to simmer for 20-25 minutes.

While your meat sauce simmers, mix together 15 ounces of ricotta cheese, 1 cup of sour cream, 1 beaten egg, and ½ cup of grated Parmesan cheese in a medium bowl. Use a spatula to blend the ingredients until smooth and creamy. Set this ricotta mixture aside.

Preheat your oven to 375°F (190°C) and lightly grease a 9x13-inch baking dish with non-stick spray or butter.

Start layering your lasagna by spreading a thin layer of meat sauce on the bottom of the prepared dish. Place three lasagna noodles on top, followed by half of the ricotta mixture. Add another layer of meat sauce, then sprinkle 1 cup of shredded mozzarella cheese over it. Repeat the layers, ending with noodles, a final spread of meat sauce, and top it all off generously with remaining mozzarella cheese.

Cover the assembled lasagna tightly with aluminum foil, ensuring it doesn’t touch the cheese. Place it in the preheated oven and bake for 30 minutes. After that, remove the foil and bake for an additional 15-20 minutes, or until the cheese is bubbly and golden brown on top.

Once baked, remove the lasagna from the oven and let it rest for 15 minutes before slicing. Serve warm.