Potato Cheese Soup

1 c. finely chopped onion
1 c. finely chopped celery
1 c. finely chopped potatoes
2 c. half & half
2 c. whole milk
1 1/2 t. salt
1 1/2 t. sugar
1/2 c. margarine, melted
3/4 c. flour
small package velveeta cheese

In large pot, place chopped vegetables, salt and sugar and barely cover with water. Simmer about 20 minutes until tender. Melt butter and whisk in flour. Add half & half to vegetables, then add butter and flour mixture. Chop up velveeta and stir in to pot until melted. Add milk to desired thickness.