Why did my cheese sauce turn grainy or gritty?
This usually happens from too much heat or adding cheese while the base is bubbling. Keep the heat low when melting the cheese, and use freshly shredded cheese if possible. Pre-shredded cheese often has anti-caking agents that can mess with smooth melting. Also, once the cheese is in, avoid cranking the heat to “fix” thickness. Just whisk in a splash of milk instead.
Can I make it without flour?
Yes. Skip the roux and thicken with a cornstarch slurry instead: mix 1 tablespoon cornstarch with 1 tablespoon cold milk until smooth. Warm 1 1/2 cups milk in a saucepan until steaming, then whisk in the slurry. Bring it to a gentle simmer and whisk for 30 to 60 seconds until it thickens and loses that raw starch vibe. Take the pan off the heat, then add cream cheese and cheddar as written (low heat is fine if needed, but do not let it boil).
What is the best cheese to use?
Sharp cheddar is the classic. For extra melt and stretch, swap in up to half Monterey Jack or pepper Jack. Avoid super aged cheddars as the main cheese because they can separate more easily.
How do I make it spicier without making it bitter?
Add heat in layers: extra hot sauce, a pinch more cayenne, or a spoonful of diced pickled jalapeños with a little brine. If it gets harsh, soften it with a tablespoon of cream cheese or a splash of milk.
Can I keep it warm for a party?
Yes. Keep it warm on the lowest setting in a small slow cooker. Stir occasionally and add a splash of milk if it thickens too much.