In a skillet over medium heat, cook the ground beef until browned and cooked through. Drain any excess fat and transfer the cooked beef to a large mixing bowl.
To the bowl with the cooked ground beef, add the diced onions, diced pickles, shredded cheese, ketchup, mustard, salt, and pepper. Mix until well combined, ensuring that all the ingredients are evenly distributed throughout the filling.
Lay an egg roll wrapper on a clean, flat surface. Spoon a generous portion of the cheeseburger filling onto the center of the wrapper. Fold the bottom corner of the wrapper over the filling, then fold in the sides, and roll tightly to enclose the filling. Seal the edge with a dab of water to ensure the egg roll stays closed during frying. Repeat with the remaining wrappers and filling.
In a deep fryer or large skillet, heat oil to 350°F. Carefully add the egg rolls to the hot oil in batches, being careful not to overcrowd the pan. Fry for 3-4 minutes, or until golden brown and crispy on all sides. Remove the cooked egg rolls with a slotted spoon and drain on paper towels to remove excess oil.
Serve the cheeseburger egg rolls hot with your favorite dipping sauces, such as ketchup, big mac sauce, or ranch dressing. Enjoy the crispy, cheesy goodness with friends and family!