Pasta with Sausage, Mushrooms and White Wine Cream Sauce

dry pasta, any medium shape (I used gemelli)

extra-virgin olive oil

bulk mild (or hot, if you prefer) Italian sausage

small onion, diced

mushrooms, thinly sliced

dry white wine (I used Sauvignon Blanc)

heavy cream

heaping tablespoon fresh chopped rosemary

nutmeg

crushed red pepper flakes (plus more for serving)

Grated Parmesan cheese