Step 1

In a small saucepan, melt the butter over medium heat. Stir in the flour until smooth. Then, gradually whisk in the milk.

Step 2

Stir in the chili powder, cumin and salt. Bring the sauce to a boil, stirring constantly. Cook and stir until thickened, one to two minutes.

Step 3

Reduce the heat to low. Add the cheese, and stir until melted. Editor's Tip: Be careful with the heat once you add the cheese. High heat can cause cheese sauces to break, where the water and oil separate and the sauce gains a curdled, grainy texture. If it happens, don't fret! Here's how to save a broken sauce.