1. Over medium-high heat saute the onions and mushrooms in 2 Tbs olive oil until soft
2. Add the garlic and red pepper flakes and cook for 30 seconds
3. Add the chicken stock to deglaze the pan and cook until reduced by half
4. Add the butter
5. Once the butter is melted and stirred in add the spinach and cook thoroughly
6. Add half of the parmesan cheese and the cooked pasta and stir to coat evenly
7. Add the olive oil and stir
8. Season to taste with salt and pepper