Preheat your oven to 375°F (190°C) and start boiling a large pot of water for the pasta.
Once the water is boiling, add a little salt and then cook the pasta according to the package instructions, aiming for al dente, which is roughly about 7 to 8 minutes. Drain the cooked pasta and transfer it to a large dish, setting it aside.
In a separate pan, heat the olive oil over medium heat. Add the Italian sausage, breaking it apart with a spatula, and cook until it’s no longer pink. Transfer the cooked sausage to a bowl and set it aside.
In another pan, heat the tomato sauce until it’s warmed through.
Combine the warm tomato sauce with the cooked pasta, mixing to coat the pasta evenly.
Transfer half of the sauced pasta into a casserole dish. Layer it with half of the shredded mozzarella and half of the cooked sausage. Then, add the remaining pasta on top, followed by the rest of the mozzarella and a little more of the cooked sausage.
Place the casserole dish in the preheated oven and bake for roughly about 10 to 15 minutes or until the cheese is golden brown and bubbly.
Once out of the oven, top the pasta bake with fresh basil leaves. Serve hot, and enjoy your delicious Sausage and Mozzarella Pasta Bake!