Heat butter in stock pot until sizzling. Add onions, garlic and red pepper flakes. Sauté until onions are softened.
Stir in rice to coat with butter. Add mushrooms, sauté until mushrooms are softened. Add wine. Cook until all liquid is absorbed. Add 1 cup broth. Stir constantly until broth is absorbed.
Continue with remaining 5 cups broth, adding 1 cup each time, until rice is creamy and has absorbed all broth. Stir in Alfredo Sauce.
For each serving, combine about 1 cup risotto, with 1 ounce spinach and 2 tablespoons broth. Heat and stir just until spinach is wilted.