Refrigerate the mac and cheese for 3-4 hours before using it in this recipe.
Add it to a large bowl, and mix with the shredded cheddar and parmesan cheese. If the texture is still a bit runny, add more cheese of choice. The mac and cheese should be firm and consistent enough to easily roll into balls.
Whisk eggs and milk into a medium shallow bowl.
In another one add bread crumbs and set them aside.
Using an ice-cream scoop, scoop and roll out about 15 balls. The number depends on the size of the balls.
Next, dip each ball in the egg wash and then dredge in bread crumbs, coat evenly. Place on a parchment paper-lined cutting board or baking sheet and refrigerate for at least 30 minutes.
Heat vegetable oil in a large stockpot or Dutch oven over medium-high heat.
Then, add the balls to the Dutch oven and cook for about 4 minutes, until evenly golden and crispy. Work in batches.
After that, transfer to a paper towel-lined plate to drain excess oil.
Serve immediately with favorite dipping sauce.