Prepare the jalapeños: Preheat oven to 400°F. Place the halved jalapeños cut-side down on a baking sheet. Bake for 15–20 minutes, or until softened and slightly darkened. Allow them to cool enough to handle, then dice into small pieces.

Stovetop option: Dice the jalapeños before cooking. Heat 1 tablespoon olive oil in a large saucepan over medium heat. Add the diced jalapeños and cook for about 5 minutes, or until softened. Sautéing jalapeños can release fumes that may irritate your eyes, so good ventilation is helpful.

Make the cornstarch slurry: Measure 1 tablespoon of the evaporated milk into a small bowl. Whisk in the cornstarch until smooth and set aside.

Heat the milk: Pour the remaining evaporated milk into a large Dutch oven or wide saucepan. Heat over medium heat until hot, but do not bring it to a boil.

Make the queso: Whisk in the shredded cheddar, cornstarch slurry, and ½ teaspoon salt. Cook for 3–5 minutes, stirring frequently, until the cheese is melted and the mixture is smooth and thickened.

Finish: Taste and add the remaining ½ teaspoon salt if needed. Stir in the diced jalapeños.

Serve: Serve immediately with nachos or tortilla chips.