01 - Cook macaroni according to package directions until al dente, then drain and set aside.
02 - In a saucepan over medium heat, melt butter. Stir in flour and cook for 1 minute to create a roux.
03 - Gradually whisk in milk. Cook, stirring constantly, until the mixture thickens, approximately 3–4 minutes.
04 - Incorporate cheddar and mozzarella cheeses, stirring until melted and smooth. Season with garlic powder, onion powder, salt, and black pepper.
05 - Add the cooked macaroni to the cheese sauce and stir to ensure even coating. Allow the mixture to cool slightly.
06 - Lay an egg roll wrapper flat with a corner facing you. Spoon approximately 2 tablespoons of the mac and cheese mixture onto the lower third of the wrapper.
07 - Fold the bottom corner of the wrapper up over the filling. Fold in both sides towards the center, then roll up tightly to form an egg roll. Brush the top corner with beaten egg to seal. Repeat with the remaining wrappers and filling.
08 - In a deep, heavy-bottomed pan, heat approximately 2 inches of vegetable oil to 350°F (180°C).
09 - Fry the egg rolls in batches for 2–3 minutes, turning occasionally, until they achieve a golden brown and crispy exterior. Drain on paper towels.
10 - Serve the egg rolls hot. Offer your favorite dipping sauce on the side if desired.