Heat 1 quart milk in saucepan. DO NOT BOIL. In separate pan, mix together ½ cup flour and ½ cup butter and cook for 2 minutes. Combine with heated milk. Make sure butter stuff isn't boiling. If lumpy, beat with beater. In a separate pan, heat half and half and ½ quart milk. DO NOT BOIL. In separate pan, mix together flour and butter and cook for 2 minutes. Combine with heated milk. Make sure butter stuff isn't boiling. If lumpy, beat with beater. Mix both batches together and add sugar.