Cheese sauce without flour?

If you have evaporated milk (also known as unsweetened condensed milk) in your pantry, you can use it to replace everything except the cheese in a cheese sauce for stovetop macaroni and cheese.

Stovetop Mac and Cheese with Evaporated Milk Cheese Sauce

This recipe is an example of mac and cheese made with an evaporated milk cheese sauce.

Ingredients

• 6 ounces (170g) elbow macaroni
• 6 ounces (180ml) evaporated milk
• 6 ounces (170g) grated mild or medium cheddar cheese, or any good melting cheese, such as Fontina, Gruyère, or Jack

Directions:

1. Place macaroni in a medium saucepan or skillet and add just enough cold water to cover. Add a pinch of salt and bring to a boil over high heat, stirring frequently. Continue to cook, stirring, until water has been almost completely absorbed and macaroni is just shy of al dente, about 6 minutes.
2. Immediately add evaporated milk and bring to a boil. Add cheese. Reduce heat to low and cook, stirring continuously, until cheese is melted and liquid has reduced to a creamy sauce, about 2 minutes longer. Season to taste with more salt and serve immediately.

The recipe does not drain the macaroni, but instead uses the remaining cooking liquid as part of the sauce. This is important, as the starch released by the pasta during cooking is needed to keep the sauce smooth.

(Consider this cheese sauce recipe, which uses a similar ratio of cheese to evaporated milk but also includes cornstarch. The "Read more" link in the recipe notes that a sauce made with just cheese and evaporated milk was significantly less smooth than a sauce made with both evaporated milk and cornstarch.)

A note for baked macaroni and cheese:

A footnote in a recipe for baked mac and cheese from the same website noted that a different cheese sauce recipe using evaporated milk did not work well in baked mac and cheese.

I found that [the cheese sauce] didn't translate as well to the baked version of the dish; it tends to break when subsequently baked, diminishing its gooey texture and cheesy flavor.

You can get the starchy thickening effect by adding some pasta water to your sauce. Here's an example recipe for the approach from Bon Appetit.

I'd possibly try this, as an experiment.

Mild cheddar melts better than mature or vintage, so I'd be tempted to try extract the best from both.

Start with butter & milk, a dash of mustard powder, salt/pepper & add very mild grated cheddar.
Heat & stir until it will combine smoothly.
Mix in your part-cooked pasta.
Add a good handful or two of vintage cheddar [the cracklier the better], cut into small cubes or broken into 'rustic chunks' - stir very briefly, don't wait for it to melt.

Oven bake - additional grated vintage cheddar, pepper &/or breadcrumbs on top depending on whether you like that crunchy top.

The mild cheddar will give you a hint of 'sauciness' even without the roux, the vintage will give you a good hit of flavour in bursts. The butter will separate out a bit - like it does by day 2 anyway - but I don't think it would spoil the presentation.

Bear in mind that even without the roux base, the liquid will be pulled into the pasta as it cooks, so start wetter than you require in your end result.

I use Instant Masa, nixtamalized, powdered corn, on place of flour for most gravies and sauces. It does not add much flavor on its own, and has a thickening strength quite similar to white flour. Making a cheesy Hollandaise, with yolks, butter, lemon juice and cheese might work. There's plenty of recipes online but, being satisfied with Masa, I've not actually tried any of them.

If I was absolutely desperate and didn't have flour, corn starch or anything similar, I'd try using breadcrumbs (ideally fine). The texture would be different, and I think I'd melt cheese into milk (no butter, and perhaps a little less milk than normal) then stir in the pasta, cooked to barely al dente, before adding breadcrumbs until it just starts to thicken. Then top with more cheese if desired and bake.

This is the sort of thing I'd try if staying in my campervan, where I don't have the usual store cupboard. It would be an experiment. I'm sure it would be edible and tasty, but you may be disappointed in the texture.