Add the Italian sausage to a large, oven-safe skillet.
Cook over medium heat, stirring to break up the ground sausage, until browned.
Add the garlic, and cook, stirring the entire time, for 1 minute.
Pour in the wine, and scrape up any browned bits from the bottom of the skillet.
Cook until the wine has reduced but half, about 2-3 minutes.
Add the tortellini and marinara. Give everything a good stir.
Sprinkle the shredded mozzarella over the top.
Cover with a tight-fitting lid or with a piece of aluminum foil.
Bake until the sauce and bubbly and the pasta is al dente, about 15-20 minutes.
Carefully uncover and broil for 1-2 minutes, if desired.
Serve topped with fresh basil.
Notes
Italian sausage: Hot or mild Italian sausage will work. You could also use ground beef or ground turkey. If you're using ground beef, you may find that you need to drain the grease before continuing. If you use ground turkey, you may need to add a bit of oil to your skillet.
Wine: If you'd like to skip the wine, beef broth or chicken broth makes a good substitute.
Marinara sauce: I recommend using a good-quality marinara sauce that has plenty of flavor.