Place milk, cream cheese, flour, and salt in a blender and blend until smooth.
In a non-stick sauce pan, melt butter on med-high heat and add garlic. Let the garlic saute for about 30 seconds, you don’t want to burn it.
Add milk mixture to the pan. Stir constantly for about 3 or 4 minutes or until it just comes to a simmer. Keep stirring and let it cook for a few minutes more. It should be much thicker now.
When it’s thickened, remove the pan from the heat. Add 1 c of the cheese, stir it up and cover immediately. Let stand for at least 10 minutes before using
While sauce is setting up and cheese is melting, wash and chop spinach.
Layer ingredients as follows in a greased glass casserole dish: 1/2 c alfredo sauce spread on the bottom,1/2 of frozen ravioli, 3/4 c spinach, 1/2 of remaining alfredo sauce, then the other 1/2 of ravioli, 3/4 c spinach, and the rest of the alfredo sauce.
Cover with foil and bake in 400* oven for 40 min or until tortellini is tender.
Remove from oven, add sliced steak, 1/2 c spinach and the remaining 1/2 c parmesan cheese.
Return to oven and bake, uncovered, for 5 min or until cheese is melted.
Allow to stand a few minutes before serving if you desire a thicker sauce.