Cook the pasta in boiling water according to the package directions. Reserve 1 cup of the pasta water before draining.
In a large skillet over medium heat, brown the sausage on both sides. Add the frozen peas and cook until the peas are heated through (about 5-7 minutes).
Add the cooked pasta to the skillet along with the parmesan and about 1/2 cup of the reserved pasta water. Stir until everything is combined. Serve hot.
Tip: I always reserve 1 cup of the pasta water just in case I want to make it a little more saucy. Add about 1/2 cup to begin with and then adjust to your desired consistency.