Add the butter to a medium saucepan and heat over medium heat.
Once the butter is melted and hot, add the garlic and sauté 20 seconds to 1 minute or until fragrant. Do not brown.
Add the diced tomatoes, green chiles, onion powder, cumin, cayenne, and garlic powder to the saucepan. Mix well and cook until the tomatoes are softened, about 2 minutes.
Once the tomatoes are soft, stir in the cornstarch and then whisk in the evaporated milk. Bring to a boil, whisking occasionally.
When the milk has come to a boil and has slightly thickened, turn off the heat. Add the cheese and whisk until smooth. Stir in the fresh cilantro and season with salt, to taste.
Serve immediately with gluten-free tortilla chips.
• Shred your own cheese from the block. The anti-caking ingredients in pre-shredded cheese may prevent the cheese from melting properly, resulting in a cheese sauce that isn’t smooth.
• Store leftovers in the refrigerator. Reheat on the stove or in the microwave. If the queso becomes too thick after reheating, thin it with a little milk, as needed.