In a large saucepan set over medium-high heat, melt the butter. Add the flour and cook, stirring constantly, for 1 minute to form a roux.

Gradually whisk in the evaporated milk, whole milk, and heavy cream. Bring the mixture to a gentle boil, whisking continuously, until thickened.

Season the béchamel sauce with 1 tablespoon of Dijon mustard, garlic powder, smoked paprika, salt, and black pepper. Taste and adjust seasoning as needed.

Reduce the heat to low and gradually fold in the grated cheddar and Monterey Jack cheeses until fully melted and incorporated. If the sauce appears grainy, blend briefly with an immersion blender until smooth.

Stir the cooked macaroni into the cheese sauce until evenly coated. Transfer the mixture to a 9x13-inch baking dish, spread evenly, and refrigerate until completely chilled.

Prepare a breading station with one bowl of crushed potato chips and another bowl containing the beaten eggs mixed with the remaining 1 tablespoon Dijon mustard.

Heat frying oil in a deep pot to 350°F (175°C).

Using a medium ice cream scoop, portion the chilled mac and cheese into uniform balls. If desired, insert a small piece of mozzarella into the center of each portion and gently shape into a ball.

Dip each ball into the egg mixture, then coat thoroughly with crushed potato chips. Place on a baking sheet while repeating with remaining portions.

Fry the mac and cheese balls in batches, 4–6 at a time, until golden brown, approximately 2–4 minutes per batch, maintaining oil temperature throughout.

Remove from the oil and drain on paper towels or a wire rack. Season lightly with salt and serve warm with preferred dipping sauces.