Preheat the oven to 350°F. Spray a 12x17-inch rimmed baking sheet with nonstick cooking spray.

Break the lasagna noodles into approximately 2-inch pieces. Cook according to the package directions until al dente. Drain and set aside.

While the noodles cook, heat a large, deep skillet over medium-high heat. Add the ground beef, Italian sausage, and diced onion.

Cook until the meat is browned and no longer pink, breaking it up as it cooks. Drain any excess grease.

Stir in the marinara sauce, Italian seasoning, ½ teaspoon salt, and ¼ teaspoon black pepper. Bring the mixture to a low simmer and cook for 3 to 5 minutes, stirring occasionally.

Add the cooked noodles and 1 cup of the mozzarella cheese. Stir gently until the noodles are evenly coated with the sauce.

In a separate bowl, stir together the ricotta cheese, spinach, the remaining ½ teaspoon salt, and the remaining ¼ teaspoon black pepper until well combined.

Spread the meat and noodle mixture into an even layer on the prepared baking sheet.

Dollop the ricotta mixture evenly over the top of the lasagna (I did 12 dollops throughout the top). It does not need to be spread into a solid layer.

Sprinkle with the remaining 1 cup mozzarella cheese and the parmesan cheese.

Bake for 20-25 minutes, or until the cheese is melted and lightly golden brown.

Let the lasagna rest for 10 minutes before serving. Serve and enjoy!