Coat large non-stick saucepan with cooking spray. Saute garlic and onion for 2 minutes.
Toss in ham and cook for 2 minutes.
Add sliced mushrooms and cook a further 2-3 minutes. Remove from pan and set to one side.
In the same saucepan melt margarine. Add flour & mix well. Slowly add in evaporated milk and then skim milk, mixing continually until smooth. Stir in dry soup mix, stock powder and parmesan cheese. Return mushroom mixture to pot, combine well, add salt and pepper to taste.