Bring a large pot of water to a boil.
Add tortellini and cook according to package directions.
Drain and set aside while you make the sauce.
While the pasta is cooking, melt 1 tablespoon butter in a cast iron skillet over medium heat.
Once butter is melted add sliced sausage and cook until browned.
Remove from pan with a slotted spoon and set aside. Keep warm.
Add another tablespoon of butter to the pan.
Add minced garlic and cook until fragrant, about 1 minute.
Pour in heavy cream and stir to combine with the garlic and butter.
Once mixture starts to simmer add the shredded Parmesan and Romano cheeses to the pan. Stir and cook until cheese is melted and sauce thickens slightly.
Stir in freshly grated nutmeg and pepper. Stir to combine.
Return sausage to the pan and stir to coat with the sauce.
Add cooked tortellini to the pan and stir to coat the pasta with the sauce.
Turn off heat and top pasta with a layer of shredded Mozzarella cheese.
Place the skillet in the oven and set oven temperature to "broil". Cook until cheese is melted, bubbly and starting to brown along the edges.
Serve immediately with a crisp green salad and garlic bread to round out the meal.