Scoop a scant 1/3 cup of the potato mixture into hot oil and press to flatten to 1/2 inch thick. Repeat, but do not crowd pan. Cook 2 to 3 minutes per side, until browned. Transfer latkes to a paper towel-lined baking sheet and keep warm in 200° F oven. Repeat with all of the potato mixture, adding remaining 1/4 cup oil to pan halfway through.