Set a large pot of water to boil, Be sure to salt the water, about ½ tablespoon of salt. While the water comes to a boil, prepare the sauce.
In a large sauce pan, heat olive oil over high heat until shimmering. Season with salt and pepper, then sauté the peppers and onions until softened but not mushy, 4 to 5 minutes. Once cooked, transfer the peppers and onions to a separate bowl then add the loose Italian sausage to the sauté pan.
Cook the Italian sausage over medium-high heat, breaking it into small pieces. (Using a potato masher is my favorite way to do this). Once the sausage is browned, add the peppers and onions back to the pan.
Deglaze the pan with half the amount of white wine, scraping the bottom of the pan for any browned bits of sausage. Stir in the pasta sauce. Add the remaining white wine to the jar of pasta sauce, cover and shake, then stir in the liquid to the sauce. Turn off heat on the sauce and preheat the oven to 375°F while waiting for the pasta to cook.
Once the pasta water reaches a roiling boil, add the pasta. Stir so the pasta doesn't clump. Cook until just al dente according the box directions. Drain and stir the pasta into the sauce.
Add half the mozzarella into the sauce, stirring to evenly distribute.
Transfer the pasta into a buttered 9x13 baking dish and top with the remaining mozzarella pieces. Bake for 20 minutes until the cheese is bubbling. Serve right away or reheat later and enjoy!