1/2 cup freshly grated parmesan cheese, plus more for garnish
Directions
Bring 4 quarts of salted water to boil in a large pot.
Melt the butter in a large pan. When the butter foams, add the onions and saute over medium heat until they are just beginning to brown around the edges, about 7 minutes.
Add the Porcini Umami and cook for 1-2 minutes.
Stir the cream into the pan and simmer just until the sauce thickens, about 2 minutes.
While preparing the sauce, cook and drain the pasta. Toss the hot pasta with the sauce and grated Parmesan. Serve immediately