Would I be able to make a cheese sauce from jarred alfredo sauce and grated cheese?

I think so, maybe add some extra milk and butter to smooth it out.

Or…you could just make a cheese sauce alone with cheese, milk and butter.

It wouldn’t be a cheese sauce, it would still be alfredo. Cheese sauce is simply milk, cheese, and cornstarch.

Try it you may like it.

If not lesson learned and you can try something else next time.

Strictly speaking it would not be a cheese sauce, but that should not be a stumbling block.

In the end, do you think it might be a pretty decent macaroni and cheese?

@Zone36 It will be macaroni alfredo.

I think it would be a bit different but probably fine. What could be wrong with carbs and dairy?

Do it! Whether it works or not, thus are great chefs made.
Seriously.

Works for me. What time’s soup on?

Sure. It’ll be delicious. Next time, if you want to be REALLY BRAVE, make your own Alfredo sauce, very easy, make a roux (melt 2 tbst butter, add same amount by volume of flour, stir together, cook a little, add 1 cup of milk, keep stirring, wait till it thickens just a bit, add ¾ cup grated cheese, add nutmeg for mystery, add salt and pepper to taste, and, VOILA. Takes much less time than perusing the ingredients lists on the Alfredo jars, rinsing them out, recycling… and you can get all high and mighty, too, like me!

Adding a pinch of mustard powder to the roux and using a little Parmesan as well as the other cheese (i use mature cheddar) works well for me.

It’s too easy to do properly to make messing about worth the effort.