Place the potatoes in a pot of boiling water and cook until tender. Drain and place in a large bowl.
Add the butter, sour cream, garlic and salt to the potatoes. Mash with a potato masher or fork until the desired texture is reached. Add the green onions in and stir to combine. Let cool on counter for about 5 to 10 minutes, until they're cool to touch.
Lay the egg roll wrappers on a clean dry surface and place about 2 to 3 tablespoons of the potato mixture in the center of the egg roll. Top with a strip of cheese and some crumbled bacon.
Brush the outer edges of the egg roll wrapper with the lightly beaten egg, then fold up the egg roll and seal shut. (click [HERE|http://www.iwashyoudry.com/2012/08/31/avocado-egg-rolls-with-creamy-cilantro-ranch-dip/] for photos on how to fold an egg roll) Repeat with remaining egg roll wrappers.
Heat oil in a deep fryer or heavy bottomed pot to 375 degrees F.
Fry egg rolls for about 2 minutes, or until they reach a golden brown color. Drain on a paper towel lined plate. Enjoy hot, dipped in a cool ranch dressing.
The Starch Foundation
Potato texture dictates whether these rolls fry successfully or burst open in the oil. Russet baking potatoes contain high levels of starch and low moisture content, which creates a dry, fluffy mash that holds its shape inside the wrapper. Waxy varieties like red or Yukon Gold potatoes retain more water and can make the filling pasty or heavy, leading to soggy wrappers during frying. Cool the mashed potato mixture entirely before assembly; putting hot potatoes onto thin wheat wrappers generates internal steam that dissolves the seal before the rolls reach the oil. Incorporating the butter and sour cream while the potatoes are still hot ensures smooth integration, but allowing that mixture to sit on the counter for ten minutes prevents premature moisture release.
Frying and Doneness
Maintaining oil temperature is the single most critical factor for achieving crisp, greaseless wrappers without scorching the exterior. Heat canola or another neutral high-smoke-point oil to 375 degrees Fahrenheit in a heavy-bottomed pot or deep fryer, and monitor it with a clip-on thermometer because adding cold rolls will drop the oil temperature. Fry small batches of three to four rolls at a time to prevent the oil from cooling down too rapidly, which causes the wrappers to absorb grease instead of frying. Cook the rolls for roughly two minutes, watching for a uniform golden brown color across the entire surface before transferring them to a paper towel-lined plate to drain.