A Better Queso

If using fresh chiles: Place 5 large fresh mild green chiles on a foil-lined baking sheet and broil until blistered, 5–7 minutes per side. Place in a bowl, cover with plastic wrap, and steam for 5 minutes. Remove skins, stems, and seeds. Chop chiles, drain on paper towels, and set aside. If using frozen or canned chiles: Drain 1 cup canned or frozen, thawed chopped mild green chiles and squeeze dry in a paper towel. Set aside.

Melt 3 Tbsp. unsalted butter in a medium pot over medium-low heat. Add 2 Tbsp. grated onion, 3 garlic cloves, finely grated on a microplane, and ½ tsp. Diamon Crystal or ¼ tsp. Morton kosher salt and cook, stirring, until lightly browned and liquid has evaporated, about 2 minutes. Whisk in 2 Tbsp. all-purpose flour and ½ tsp. ground cumin and cook until lightly browned, 30–60 seconds.

Raise heat to medium and slowly whisk in 1½ cup whole milk. Continue whisking until sauce is thick enough to coat the back of a spoon, about 5 minutes, then lower the heat to medium-low and add the 4 cups (16 oz.) freshly grated cheddar cheese, ¼ cup at a time, followed by 2 cups (8 oz.) freshly grated Monterey Jack cheese, ¼ cup at a time, stirring until cheese has melted completely before adding more cheese.

Stir 2 plum tomatoes, seeded and diced, and reserved chiles into the melted cheese mixture. If you prefer a thinner queso, add up to ½ cup more whole milk. Taste and adjust seasoning. Sprinkle with  roughly chopped cilantro (for serving) and serve immediately with white corn tortilla chips. Do Ahead: Prepare queso the morning of game day, then reheat on the stovetop over medium heat (or keep it warm in a slow cooker).