Mix vigorously over high heat with a whisk until no longer lumpy.
Once the lumps have gone, turn down heat to medium, grab a spatula and mix from the bottom of the pan. Once the flour has warmed up, the mixture will start to thicken and bubble a little.
If you can start to see the bottom of the pan whilst stirring, then the mixture is thick enough and ready to use. This should take about 6-7 minutes.
Once you are used to making white sauce, you can mix Step 3 over medium-high heat. This will save time and it's what I always do.
I used this sauce to make a macaroni and shrimp au gratin and put it in my lunchbox.
I also used it to make a hamburger doria packed lunch Add some rice to a dish, cover with a burger patty and meat sauce, then add the white sauce, cover in cheddar cheese and bake in the oven!
Story Behind this Recipe
I found this recipe in a very old children's recipe book from decades ago. I changed bits and pieces, made the amounts easier to remember and added some stock for flavor.
Don't leave the pan even for a second, keep paying attention and don't stop stirring! You don't have to cook the flour in this recipe so it's thankfully really hard to get wrong! You can use this basic sauce as-is on au gratin and doria dishes. Or you can add milk to stretch it out with soup to add it to a variety of dishes. It's freezable too.