1. In a 12-inch nonstick skillet, brown sausage over medium-high heat for 3-5 minutes. Transfer to a plate and keep warm.
2. In the same skillet, bring water to a boil.
3. Add pasta, reduce heat, stir often until pasta is al dente, about 8-10 minutes. (Do not drain).
4. In a small bowl, whisk cornstarch, milk and hot pepper sauce.
5. Gradually add to pasta; cook and stir until slightly thickened, about 2 minutes.
6. Remove from heat; add cheeses and sausage. Stir until blended and cheese melts.
7. Sprinkle with crumbs if desired.