Step 1

Melt the butter in a heavy-bottomed Dutch oven over medium heat.  Saute the onion and peppers until they are soft, roughly 5 minutes, stirring occasionally with a large wooden spoon.

Step 2

Add the minced garlic and the tomatoes and cook until fragrant, roughly a minute, while constantly stirring.

Step 3

Pour in the whole milk and heavy cream while whisking, then sprinkle in the chipotle pepper powder.

Step 4

In a small bowl, make a cornstarch slurry by mixing equal parts water to cornstarch.  Mix with a fork until smooth, then gradually add it to the hot milk mixture, whisking constantly.  The cornstarch will make the sauce glossy and gluten free.

Step 5

Bring the sauce to a near boil, then reduce the heat and let it simmer until thickened, whisking constantly to prevent lumps or burnt spots.  This will take roughly 10 to 12 minutes.

Step 6

Remove the Dutch oven from the heat and stir in the grated cheese in batches until it is melted.

Step 7

Taste then add enough salt to your liking.  Adjust other seasonings, if necessary.

Step 8

Serve while warm.  Keep the sauce warm by turning the stove to the lowest setting or transfer the queso blanco to a small crockpot and keep on the warm setting.