Preheat oven to 375 degrees F.
In an oven-proof 10-inch sauté pan or deep skillet with a lid, cook the ground beef and Italian sausage (casings removed) over medium-high heat. Drain the extra fat and moisture. If needed, cook in batches. Tip: For ease, carefully absorb the extra fat and moisture in the skillet with paper towel.
Make some room in the center of the skillet. Heat a few drizzles of olive oil and add the diced onions and minced garlic. Cook until fragrant, stirring, about 1-2 minutes.
Stir in the marinara sauce, Italian seasoning, and fresh basil until combined. Season with salt and pepper to taste. Bring to a simmer.
Break up the lasagna sheets into medium-sized pieces. Add the broken up lasagna noodles into the sauce. Simmer with the lid partially covered for 18-20 minutes until al dente and softened, stirring occasionally. Make sure the noodles are fully covered in the sauce.
Then, stir in 1 cup of the mozzarella cheese and simmer for another 1 minute to melt. Then, add dollops of ricotta cheese, gently pushing it down but still visible on top.
Sprinkle the lasagna with the remaining 1 cup shredded mozzarella cheese on top. Transfer to the preheated oven and bake for 8-10 minutes, until the cheese is melted and bubbly. Let cool slightly and garnish with fresh basil. Enjoy!