Grate or chop the American/processed cheese and cheddar so they melt evenly. Chop pickled jalapeños finely and drain the diced tomatoes with green chiles. Mince the garlic and chop cilantro if using.

Make a light roux

In a medium heavy-bottomed saucepan set over medium heat, melt the butter. Stir in the flour and cook for 30–45 seconds, whisking constantly, until fragrant but not browned. This will thicken the queso slightly.

Add milk and cream

Slowly whisk in the whole milk and heavy cream. Continue whisking and bring the mixture to a gentle simmer (small bubbles at the edge), about 2–3 minutes. Do not boil.

Melt cheeses

Reduce heat to low. Add the shredded/chopped cheeses in small handfuls, stirring or whisking constantly until each addition is fully melted and smooth before adding more. Keep the heat low to prevent grainy cheese.

Flavor the queso

Stir in the chopped pickled jalapeños, 1 tablespoon pickling liquid, the drained tomatoes with green chiles, minced garlic, ground cumin, kosher salt, and black pepper. Taste and adjust seasoning. If the queso is too thick, thin with up to 2 tablespoons of milk or reserved pickling liquid.

Finish

Once smooth and well combined, remove from heat. Stir in lime juice and chopped cilantro if using. Transfer the queso to a warm serving bowl. Keep warm over a double boiler or in a 150–170°F (65–77°C) oven if not serving immediately to prevent skin from forming.

Chips & Garnish

Arrange tortilla chips on a large platter or individual bowls near the queso. Spoon the warm queso into a shallow bowl placed among the chips.

Top the queso with sliced extra pickled jalapeños and a light sprinkle of crumbled queso fresco or cotija if using. Serve immediately so chips stay crisp.

Leftovers: Refrigerate queso in an airtight container for up to 4 days. Reheat gently over low heat, stirring and adding a splash of milk to return to a dip consistency.