In a small saucepan, combine 2 cups cheddar pepper cheese and 1 tablespoon cornstarch. Toss until cheese is evenly coated.
Stir in 12 ounces evaporated milk and 1 teaspoon kosher salt. Heat over medium heat, whisking occasionally, until cheese is melted and smooth, about 3 to 5 minutes. Reduce heat to low, cover, and keep warm until serving time.
Notes
Cheese can be transferred to a slow cooker and kept warm
I found the best Pepper Cheddar Cheese (similar to pepper jack) at Costco. I know Trader Joe's carries a nice variety too. If you can't find a pepper infused cheddar, you can use plain cheddar and make it spicy with cayenne pepper, red pepper flakes, green chile, salsa, hot sauce, and/or chili powder
You can also replace some or all of the cheddar cheese with pepper jack.