Cook pasta according to package.
Cook chicken sausage according to package. Set aside to cool, then slice into small bites.
Make alfredo sauce according to directions below. When alfredo sauce is done, set aside.
Mince garlic and set aside.
Slice mushrooms and set aside.
Chop spinach and set aside.
Heat large skillet over medium heat and add olive oil.
Add mushrooms and let cook for 10 minutes, stirring occasionally.
Add baby spinach and cook until spinach has wilted.
Add pasta and alfredo sauce mix well.
Turn off heat and garnish with grated parmesan cheese and red pepper flakes (if using).