
1 x level tablespoon - butter (or margarine),
2 x heaped tablespoons - flour (any type),
3 x cups of milk
Toss all into a pot and put on moderate heat. Whisk and continue gently whisking till it comes to the boil, then turn down, add a pinch of salt and milk to keep a runny consistency.
If you want a 'flash tasting' sauce, add some finely chopped fresh garlic, but cook in for 1 minute. Easy as...
If lumps did form, just add some grated cheese before serving...no one will know the difference. (The lumps are because you stopped whisking or had the heat to high).