To get the perfect light, pillowy batter layer on fried, cheese-stuffed chiles rellenos, you must separate the eggs for your batter. Whisk flour and water into the yolks, then beat the egg whites until they’re stiff and fold them into the yolks in two or three additions. TongoRad uses 4 eggs, 4 tablespoons flour, and 1 tablespoon water to make the batter, and says to dredge the chiles in flour before dipping them in the batter, and to make sure there’s a thick coating of batter on each chile before frying.
Sherri shares this “cheat” for battering and frying chiles rellenos: Make your batter as above, but don’t dip the stuffed chiles. Heat a 1/2 inch of oil until almost smoking in a cast iron skillet, and spoon some batter into the oil in the oblong shape of a chile. Lay a stuffed chile on the batter in the pan and cover it with more batter. When the bottom side is golden, turn it carefully and cook the second side.
Board Links: Homemade Chile Rellenos–Any Helpful Hints?