White Sauce

1 tbsp butter
2 tbsp plain flour
1&1/2 cup milk
stock powder
1 cup grated cheese

1. Melt butter;
2. Add flour and cook briefly;
3. Add small amount of milk and whisk briskly to avoid lumps;
4. Quickly add more milk, stir in well, then add rest of milk;
5. Bring to boil on gentle heat, stirring continuously;
6. Add stock to taste;
7. Take off heat and stir cheese through.