Stir in diced pickles, ketchup, mustard, salt, and pepper, cooking for another 2-3 minutes until well combined. Remove from heat.
Allow the mixture to cool slightly, then mix in shredded cheddar cheese until evenly distributed.
To assemble eggrolls, lay a wrapper with a corner pointing towards you and put about 2 tablespoons of the beef mixture in the center.
Fold the bottom corner over the filling, folding in the sides and then rolling tightly towards the top corner. Moisten the top corner with water to seal.
Heat about 2 inches of vegetable oil in a deep pan over medium-high heat until hot, around 350°F (175°C).
Carefully fry 3-4 eggrolls at a time until golden brown and crispy, about 3-4 minutes, flipping occasionally.
Remove cooked eggrolls and drain on paper towels. Repeat with the remaining eggrolls.
Serve warm with extra pickles, ketchup, or mustard for dipping.
Notes
Can be baked at 400°F for 20-25 minutes if preferred.