Prepare the Filling: In a large mixing bowl, combine the shredded corned beef, chopped sauerkraut, Swiss cheese, cream cheese, Dijon mustard, garlic powder, onion powder, and black pepper. Mix well until fully combined.

Shape the Balls: Using your hands, form the mixture into small balls, about 1 inch in diameter. Place the balls on a baking sheet lined with parchment paper.

Set Up the Breading Station: In one shallow dish, place the flour. In another dish, place the beaten eggs, and in a third dish, place the breadcrumbs.

Bread the Balls: Roll each ball first in the flour, then dip it into the beaten eggs, and finally coat it with breadcrumbs. Return the breaded balls to the baking sheet.

Fry the Balls: Heat oil in a deep skillet or fryer over medium heat. Once the oil is hot, carefully add the Reuben balls in batches, frying until golden brown and crispy, about 3-4 minutes per side.

Drain and Serve: Once fried, remove the balls from the oil and drain on paper towels. Serve the Crispy Reuben Balls warm with additional Dijon mustard or your favorite dipping sauce.