2 tablespoons diced canned jalapeños or chiles, drained of all additional liquid
½ teaspoon freshly ground black pepper, plus more to taste
1 cup panko bread crumbs
1 teaspoon vegetable oil
Kosher salt to taste
Prepare the mac 'n cheese according to the box directions, but reserve 1 teaspoon of the cheese powder for later.
While the mac 'n cheese is still hot, add the cheddar and American cheeses and cook, stirring until melted, 1-2 minutes. Stir in the jalapeños and black pepper and remove from the heat.
Line a small baking sheet with parchment paper. Let the mac ‘n cheese mixture cool to room temperature, then form into 12 equal-sized balls and place on the baking sheet.
Chill in the fridge for 1 hour. Preheat the oven to 350°F. Combine the panko and oil in a bowl, then roll the chilled mac ‘n cheese balls in the panko until coated. Spray a 12-inch compartment mini muffin tin with cooking spray and place one mac 'n cheese ball in each compartment (or return to the parchment-lined baking sheet).
Bake until crisp and golden, 13 to 15 minutes. Remove from the oven, season with salt and pepper, and sprinkle with the reserved 1 teaspoon cheese powder. Transfer the mac ‘n cheese balls to a plate and serve immediately.