Melt 11⁄2 tbsp butter in a medium pot, add 11⁄2 tbsp flour and cook over a low heat, stirring for one minute. Whisk in 1 can Nestlé Ideal Unsweetened Evaporated Low Fat Milk and 1 tsp salt. Bring to the boil, lower heat and cook for five minutes, stirring occasionally until sauce has thickened. The sauce is ready when it lightly coats the back of a spoon. USE FOR: making creamy pasta, veg and baked potatos.