Brown the sausage and onion

• Heat a large skillet over medium‑high heat.

• Add the Italian sausage (remove casings if using links) and the chopped onion.

• Cook until the sausage is fully browned and the onion is softened, stirring occasionally, so it all cooks evenly.

• Drain excess grease from the skillet to avoid a greasy sauce later.

Build your sauce

• Reduce heat to medium‑low.

• Add minced garlic and cook briefly until fragrant (about 30 seconds) to avoid burning.

• Pour in the Alfredo sauce and marinara sauce.

• Stir in Italian seasoning and red pepper flakes.

• Mix until smooth and well combined.

Add the tortellini and cook until tender

• Add the frozen cheese tortellini into the skillet.

• Stir to coat the tortellini well with the sauce.

• Cover the skillet with a lid.

• Let it cook for several minutes, stirring sometimes, until the tortellini is heated through and tender (follow package directions, usually 5–7 minutes).

Melt the mozzarella topping

• Preheat your oven to 400°F (about 200°C).

• Sprinkle shredded mozzarella cheese evenly over the top of the pasta in the skillet.

• Place skillet into the oven for just a few minutes until the cheese melts and bubbles.

• (Alternatively: Stay on the stove with lid on—just cover until cheese above just melts.)

Garnish and serve

• Once the cheese is melted, remove from oven or stove.

• Sprinkle dried parsley flakes on top for color and a little fresh flavor.

• Serve immediately, while piping hot