Add alfredo sauce mix, water and vegetable broth to slow cooker and whisk until smooth. Stir in broth, mushrooms, onion, garlic, basil, salt, oregano, and cayenne pepper.
Cover and cook on low heat for 6 hours or high for 3 hours. If you happen to be home, a stir mid-cook time is helpful to keep the mushrooms moist but not crucial.
Stir in tortellini and cook on low for an additional hour on low or for an additional 30 minutes on high. Add about thirty minutes to both cook times if your pasta is dried as opposed to fresh.
Just before serving, stir in evaporated milk and spinach leaves until well combined.
Serve immediately with a sprinkle of fresh ground black pepper and enjoy!
Recipe by Bake Love Give at http://bakelovegive.com/creamy-tortellini-soup/