Step 1

Toss the shredded cheese with the cornstarch; set aside.

Step 2

Place the butter in a medium saucepan over medium heat; add the onion, pepper, cumin, and salt, and cook, stirring occasionally, until the onions start to soften and become translucent, about 4 minutes.

Step 3

Add the garlic and cook for 1 minute more. Add the milk and bring to a simmer.

Step 4

A handful at a time, add the cheese to the saucepan, stirring after each addition until melted. Let the queso simmer for 2 to 3 minutes. Taste the dip (caution—it's hot!) and adjust for seasoning (be careful with salt because tortilla chips are usually already pretty salty).

Step 5

Transfer the queso to a bowl. Top with some cilantro and serve with tortilla chips for dipping.