Rather than boiling the noodles in a separate pot, we cooked them with the chicken stock and other ingredients. The starch from the pasta thickens the broth, making a surprisingly rich sauce without butter or cream.
2 teaspoons olive oil
12 ounces fully cooked sweet Italian-style chicken sausage (such as Al Fresco), cut into 1/4-inch-thick slices
Heat oil in a large, high-sided skillet over medium-high. Add sausage and mushrooms; cook, stirring often, until browned, about 8 minutes. Add stock and next 5 ingredients; bring to a boil. Cook, stirring constantly, until pasta is al dente and liquid is mostly absorbed, about 15 minutes. Stir in vinegar, and sprinkle with crushed red pepper.