Heat vegetable oil in a medium saucepan over medium-high heat until shimmering.
Add onion and cook, stirring often, until golden brown, about 5 minutes.
Stir in chipotle and garlic and cook until fragrant, about 30 seconds.
Stir in drained tomatoes and cook until warmed, about 1-2 minutes. Transfer to a small bowl.
MELT CHEESE:
Add half-and-half and cornstarch to the now-empty pot, and whisk together until combined.
Bring to simmer, then reduce heat to low and whisk in shredded cheese until melted.
Stir in tomato mixture and salt. Let sit for 10 minutes to thicken slightly.
FINISH AND SERVE:
Stir in cilantro, and serve with tortilla chips.
Video
Notes
The nutrition information below is just for the queso dip. It doesn't include tortilla chips.
Please, please, PLEASE only use freshly grated cheese for this Chile con Queso recipe. The pre-shredded variety has anti-clumping additives that add a grainy texture to this queso dip.
This chile con queso doubles nicely. Just make sure you use a large saucepan when making a double batch.