Make the Balls:

1. Prepare Baking Sheet:
   1. Line a baking sheet with parchment paper.
2. Combine Mac and Cheese:
   1. Add cold mac and cheese to a large bowl.
   2. Add the shredded Monterey Jack and Colby Jack cheeses.
   3. Mix thoroughly, using your hands for easier combining.
3. Shape Balls:
   1. Scoop out portions of the mac and cheese mixture and roll them into 2-inch balls.
   2. Place the balls on the prepared baking sheet.
   3. Repeat with the remaining mac and cheese.
4. Prepare Dredging Stations:
   1. In a shallow dish, combine the flour, salt, pepper, onion powder, and garlic powder. Stir to combine.
   2. In a separate shallow dish, beat the eggs until smooth.
   3. In a third shallow dish, add the seasoned panko breadcrumbs.
5. Dredge and Coat:
   1. Roll each mac and cheese ball in the flour mixture.
   2. Dip the ball into the beaten egg, allowing excess to drip off.
   3. Roll the ball in the panko breadcrumbs, ensuring all areas are coated.
   4. Place the coated ball back on the baking sheet.
   5. Repeat with the remaining balls.
6. Freeze:
   1. Cover the baking sheet and freeze for at least 30 minutes.

Fry the Balls:

1. Prepare for Frying:
   1. Remove the baking sheet from the freezer.
   2. Line a baking sheet with paper towels and place a cooling rack on top.
2. Heat Oil:
   1. Use a heavy-bottomed pan (like a Dutch oven) and add vegetable oil to a depth of 3-4 inches.
   2. Attach a candy or oil thermometer to the pan and heat the oil over high heat.
   3. Once the oil reaches 360°F (182°C), gently lower 4-5 balls into the hot oil using a spider or tongs.
3. Fry:
   1. Set a timer for 4 minutes and turn the balls occasionally until golden brown and crispy.
   2. Adjust the heat as needed to maintain a temperature between 350-375°F (177-190°C).
   3. (If balls brown too quickly, remove them early to prevent burning.)
4. Drain and Serve:
   1. Remove the fried balls from the oil and place them on the cooling rack.
   2. Sprinkle with flaked sea salt and parsley (if desired).
   3. Serve immediately.