1. Bring a medium-large pot of water with a pinch of salt to a boil. Once boiling, add in your pasta and let it cook for approximately 10 minutes.Before straining, reserve 1/3 cup of pasta water for later use.Strain the pasta and set it aside.
2. Prepare your vegetables by cutting them as indicated.
3. Heat a large pan with a splash of oil over medium-high heat. Once hot, add in your diced shallots and mushrooms and cook for 8 minutes, until they begin to brown around the edges. Next, add in your stroganoff sauce, the reserved 1/3 cup of pasta water (if you forgot, just add 1/4 cup of regular water), and the pappardelle pasta. Let it cook until the sauce thickens and clings to the noodles, approximately 4 minutes.
4. To serve, place the pasta in a bowl and garnish with parsley, a drizzle of sour cream, and a pinch of salt and pepper.