In a dutch oven melt the butter over medium heat. Add the flour, mustard powder, salt, garlic powder, onion powder, and black pepper, whisk for 30 seconds.
Slowly add the milk a little at a time while whisking, this will help prevent lumps. Bring to a simmer, whisking constantly and simmer for 3 minutes. Take off the heat, whisk your egg and then temper in the egg.
Add ¾ of the cheese and stir it in until melted.
Then, add the cooked macaroni and stir to combine.
Pour into a greased 9x13-inch baking dish and top with the remaining cheese.
Place in the oven and bake for 30 minutes until the cheese on top is melted and it is bubbly.
Remove from the oven and let cool on the countertop completely.
Place the mac and cheese in the refrigerator for 6 hours or overnight.
Line sheet pans with parchment paper, set aside.
Once chilled, roll 1 ½ Tablespoons of the mac and cheese in your hands to form balls. Place on a prepared sheet pans and place in the freezer for 30 minutes.
While the mac and cheese balls are freezing, start to heat up 3-4 inches of peanut oil in a dutch oven to 350 degrees F.
Place the eggs in a small bowl and whisk.
In a medium sized bowl add the panko, garlic powder, onion powder, and black pepper and stir to combine.
One at a time, place the mac and cheese balls into the egg making sure it is coated, let any excess egg drip off.
Then, place into the breadcrumbs and coat the ball in the crumbs, gently pressing them in so they stick.
Place back on the parchment-lined sheet pan and repeat with the remaining ingredients.
Gently place the balls in batches into the hot oil, about 4-5 at a time. Fry, moving them gently around so they don’t burn on the bottom until dark golden brown, about 3-4 minutes.
Place the fried mac and cheese balls onto a paper-towel-lined plate letting any excess drip oil off them, then transfer to a wire rack placed over a sheet pan. This will help them to stay crispy all over. You can keep them in a warm 170°F oven. Repeat with the remaining mac and cheese balls.
Serve with ranch dressing for dipping if desired.