in a wide, 5-quart heavy pot over medium-high, heat 2 inches of vegetable oil to 375 f. working in batches of 5 or 6, carefully add the doughnuts, 1 at a time, to the oil and fry, turning over frequently, until browned, about 2 1/2 minutes per batch. transfer the fried doughnuts to paper towels to drain.