Place ribeye in freezer for 1 hour.
Remove from freezer, and thinly slice.
Whisk egg in a small bowl; set aside.
In medium sauté pan over medium heat, add olive oil and onion.
Sauté onion until translucent and soft, 5-6 minutes.
Add ribeye and sauté until steak is slightly pink, about 5 minutes more.
Sprinkle with salt and pepper.
Add cheese and mix thoroughly until cheese begins to melt.
Remove from heat, and strain in a fine mesh sieve if there is liquid in the pan.
Let cool slightly.
Add oil to a medium Dutch oven, filling 3/4 of the way to the top.
Preheat oil to 360°F.
Equally divide ribeye mixture in the center of each egg roll wrapper.
Fold wrapper in about 1/2 inch on each side.
Brush egg roll wrappers with egg wash.
Roll up and seal edges.
Place egg roll in oil, and fry for 3-4 minutes until golden brown, making sure to flip egg rolls while frying.
Fry in batches to avoid over-crowding.
Remove egg rolls to a paper-towel-lined plate.