Heat a large skillet over medium heat. Add the ground beef, diced onion, and minced garlic. Cook until the beef is fully browned and the onions are soft, breaking the beef into smaller pieces. Season with salt and black pepper to taste.

Remove the skillet from heat and let the mixture cool for a few minutes. Stir in the shredded cheddar until it melts and the filling comes together.

Lay an eggroll wrapper on a clean surface with one corner facing you. Spoon about 2 tablespoons of the beef mixture near that corner.

Fold the bottom corner over the filling, fold in both sides snugly, and then roll it up tightly, using a dab of water on the final corner to seal.

Heat oil in a deep skillet or fryer. Fry eggrolls in batches, turning occasionally, until golden brown and crisp (about 2 to 4 minutes per batch).

Transfer cooked eggrolls to paper towels to drain excess oil and serve hot.