01 - In a large bowl, combine shredded chicken, buffalo wing sauce, mozzarella cheese, blue cheese if using, celery, green onions, garlic powder, and black pepper. Mix thoroughly until evenly incorporated.
02 - Place an egg roll wrapper on a clean surface with a corner facing you. Spoon 2 to 3 tablespoons of the filling onto the center. Fold up the bottom corner over the mixture, fold in both sides, and roll tightly. Brush the upper corner with beaten egg to seal the roll securely.
03 - Repeat the folding and sealing process with remaining wrappers and filling, arranging each prepared roll seam-side down.
04 - Pour vegetable oil into a deep pot or fryer to a depth of approximately 2 inches. Heat to 350°F (175°F), verifying temperature with a thermometer.
05 - Gently lower egg rolls into the hot oil in batches, without crowding the pot. Fry for 3 to 4 minutes, turning as needed, until golden brown and crisp. Transfer to paper towels to drain excess oil.
06 - Arrange egg rolls on a platter and serve warm, accompanied by ranch or blue cheese dressing for dipping.