Place all ingredients, EXCEPT for cooked pasta, spinach and cheeses) in a slow cooker. Cover and cook on low 7 to 8 hours or until bubbly. Increase slow cooker to high; stir in pasta, spinach and cheeses. ( I add the pasta already cooked) Cover and cook for 10 minutes or until heated through and cheeses are melted. ( It may be done sooner since pasta is cooked. You just need the cheeses melted)
For those that are on low carb diets, or not big fans of pasta, this is also delicious over spaghetti squash.