First, I bring a large pot of salted water to a boil. Cooking the fettuccine until al dente ensures it’s perfectly tender but still holds its shape. I always save ¾ cup of the pasta cooking water to help the sauce cling to the noodles later.
I heat the oil in a skillet and cook the sausage until nicely browned, breaking it up with a wooden spoon. Adding the shallot and leeks after gives the sauce sweetness and depth without overpowering the sausage’s spice.
Next, I add the mushrooms and cook them slowly. It’s important to let the liquid from the mushrooms evaporate so the flavors concentrate and the mushrooms start to caramelize.
I briefly cook the garlic until fragrant, then melt the butter and add white wine. Once it boils, I stir in chicken stock and fire-roasted tomatoes. The sauce simmers for about 30 minutes, thickening beautifully and marrying all the flavors.
Finally, I toss the cooked fettuccine directly into the sauce with the reserved pasta water and minced parsley. The pasta absorbs the flavors perfectly, giving a glossy, well-coated finish.