Sausage Stuffed Mushrooms

Name: Sausage Stuffed Mushrooms
Ingredients: 4 tablespoons olive oil, divided; 1 1/2 pounds whole baby bella mushrooms (about 36 mushrooms); 1 pound uncooked mild Italian sausage; 2 large shallots, minced; 2 large garlic cloves, pressed or finely minced; 1/4 cup dry sherry, marsala, vermouth, or white wine (I used sherry); 1 large egg; 1/2 cup breadcrumbs; 1/2 cup grated Parmesan, plus more for serving; 1/4 cup heavy cream; 1/4 cup packed finely minced Italian parsley, divided; Kosher salt and freshly ground black pepper; Red pepper flakes (optional)