2026-09-13 18:01:42 EDT

M: I made some mac and cheese from scratch. What's the best way to heat it up once it's been in the fridge for a couple days? The pasta is elbows. The sauce is kind of a flour— sorry. It's the cheddar and American slice mix with some roux in it, and I'm trying to bring it back to a good consistency. Check online to verify rates, please.

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G: For your particular mac and cheese—elbows with a roux-based cheddar/American sauce—the best way to get it creamy again is gentle stovetop reheating with a little milk. The American cheese actually helps because its emulsifying salts make the sauce more resistant to breaking.

A good verified starting ratio is 1 tablespoon of milk per 1 cup of cold mac and cheese. The Kitchn recommends exactly that ratio, with medium-low heat for stovetop reheating. citeturn0search10turn0search15

For about 2 cups, I'd do this:

  1. Put the cold mac in a small saucepan and break it into chunks. Add 2 Tbsp milk.
  2. Heat on low to medium-low, preferably covered for the first couple minutes. Once the bottom begins loosening, gently fold/stir it rather than beating it continuously.
  3. As the sauce melts, judge the consistency. If it's still thick or pasty, add milk 1 teaspoon to 1 tablespoon at a time. Don't dump a lot in initially—the roux will loosen substantially as it gets hot.
  4. Once it's creamy and completely hot, stop. Prolonged/high heat is what risks making the cheese sauce oily or grainy. citeturn0search10

If you're doing one bowl in the microwave, use the same 1 Tbsp milk/cup, cover it, and use 50% power for 1 minute, stir, then 30-second intervals at 50% power until hot. That's considerably better for this kind of sauce than blasting it at full power. citeturn0search10

One useful trick specific to your recipe: don't add more cheese at first. Your existing cheddar/American/roux emulsion probably doesn't need more fat or solids; what it lost in the refrigerator is primarily available moisture. Get the milk incorporated first. If afterward you want it richer, then a small piece of American cheese or a little butter can help.

And since you said it's been refrigerated for a couple of days, you're within USDA's normal 3–4 day refrigerated-leftover window, assuming it was refrigerated promptly. USDA's safety target when reheating leftovers is 165°F throughout. citeturn0search0turn0search6

Bottom line: low heat + ~1 Tbsp milk per cup is where I'd start. With your roux/American-cheese combination, you have a pretty forgiving sauce for bringing back to life.