Cut mushrooms into 1/4" slices. Peel and mince shallot. Stem parsley. Rinse sausages, pat dry, and on a separate cutting board, slice each sausage link into 5 pieces.

Heat 1 tsp. olive oil in a medium pan over medium heat, add sliced Italian sausage, and cook for 5-7 minutes, or until links reach a minimum internal temperature of 160 degrees. Transfer sausages to a plate. Drain (never down the sink!) off all but 2 tsp. of rendered fat from sausages for cooking mushrooms later.

Add pasta to boiling salted water and cook 8-10 minutes, or until al dente (Italian for "to the tooth", meaning it still has a little bite or firmness). Drain in colander, return to pot, toss with 1 tsp. olive oil, and set aside.

Heat pan with rendered fat over medium heat. Add mushrooms and shallot and cook until mushrooms have released their moisture and shallots have softened, 5-6 minutes. Sprinkle with red pepper flakes (use a pinch at first, then add more to taste). Add red cooking wine and cook for another minute, scraping caramelized meats and vegetables from bottom of pan. Using wine to loosen caramelized bits of food from the pan is called "deglazing" and is a classic cooking technique.

Add canned tomatoes and their juices, mascarpone, grated Parmesan (reserving 2 tsp. for garnish), and cooked Italian sausage. Season with a pinch of salt and pepper. Simmer 5 minutes while stirring continuously.

In a bowl or plate, place a serving of pasta and ladle a generous portion of sauce on top. Garnish with parsley and remaining Parmesan cheese.