Cut the cheese into thin sticks that fit the wrappers, leaving room on both sides for folding.
If using 8-inch wrappers, cut each one in half to make two triangles.
Lay a wrapper flat with the pointed end facing away from you. Place the cheese near the straight edge. Fold the bottom over the cheese, fold in both sides, then roll tightly. Seal the edge with egg wash or a cornstarch-water mixture.
Heat enough oil to cover the lumpia over medium heat. Dip the end of one roll into the oil — if it bubbles right away, the oil is ready.
Fry in batches until crisp and light brown. Do not crowd the pan.
Drain on a wire rack or paper towels. Serve hot with your favorite dipping sauce.
Notes
Cheese: Eden or Quickmelt holds its shape and leaks less. Mozzarella, cheddar, or Colby Jack also works, but seal the wrappers well.
Lumpia wrappers: Use any size or cut them to fit. Check for holes and wrap the cheese snugly to prevent leaks.
Dipping sauce: Mix mayonnaise with sriracha, ketchup, or sweet chili sauce to taste.