Preheat the oven to 350°F. Line a 9” x 13” rectangular baking pan with parchment paper (you can also use a rectangular casserole dish). In a large pot, bring 3-4 quarts of water to a boil for cooking pasta. Shred the cheese and mix well in a large bowl. Set aside.

Once the water is at a boil, add 2 tablespoons of kosher salt or the amount needed for the water to “taste like the sea.” Cook the pasta according to the package directions for al dente, less than one minute. Drain and set aside.

Rinse out the pot of starchy residue and return it to the stove on medium heat. Melt butter and quickly add flour, whisking for 2 minutes until the roux is lightly golden but not brown. Slowly whisk in milk, followed by Maille Dijon Original mustard, smoked paprika, salt and black pepper. Continue cooking for 2 minutes on a gentle simmer (do not boil vigorously) until thickened and smooth. 

Off heat, add half the shredded cheese in several additions, stirring until the cheese is melted and sauce is smooth. Add cooked pasta and toss to coat well. Note: The mixture should be pretty thick and not as wet/saucy as mac and cheese is typically at this stage since it will be baked, cooled, and cut into cubes for mac and cheese bites. Do a final taste and season only with salt and black pepper if needed.

Transfer half the mixture into the baking pan, sprinkle with half of the remaining cheese, followed by the rest of the Mac and Cheese mixture. Spread to get an even, flat surface. Top with the remaining shredded cheese. Bake for 20-30 minutes or when it bubbles; the top is lightly golden. Cool completely to room temperature. I usually make this the night before, so I transfer it into the fridge overnight, but you can proceed with the recipe as soon as the Mac and Cheese is thoroughly cooled and set, and it can be cut into cubes easily.

Use the parchment paper flaps to lift and transfer the Mac and Cheese onto a cutting board. Cut it into cubes approximately 1½” (6 x 8, which means you should have 48 cubes).

Set out three shallow dishes. Place flour in the first dish, an egg whisked with water and salt in the second dish, and panko in the third dish. Dredge each Mac and Cheese cube in flour on all sides, shake off excess, dip in egg wash, and coat well with panko all over. Place on rack and repeat with the remaining cubes. 

Preheat the air fryer at 360°F for 5 minutes. If using, place the parchment liner in the drawer. Spray the bottom of the air fryer basket with a light coating of oil. In batches, arrange the Mac and Cheese cubes in a single layer, with about ¾” spacing around each piece to ensure even heat all around. Spray with oil. Air fry for 5 minutes, flip, spray again with oil, and air fry for 5 minutes more. Transfer the batches to the cooling rack and continue with the remaining cubes.