Melt butter in a large pot or skillet over medium heat.

Add onion and cook until softened and translucent  (about 5 minutes).

Add garlic and cook until fragrant (about 30 seconds), then add tomatoes and chilis and cook until well-combined.

Sprinkle cornstarch over the ingredients and use a spatula to stir and cook until absorbed and no lumps remain.

Add cumin, chili powder, paprika, cayenne , pepper, and salt.

Gradually drizzle evaporated milk into the pot while whisking. Cook, stirring or whisking, until milk is completely combined, warmed, and slightly thickened.

Turn stovetop heat to low and add shredded cheese.  Stir until cheese is melted and completely combined.

Taste-test and add salt and pepper (and additional cayenne pepper if you like some heat!) as needed. Serve and Enjoy!