Toss potato, onion and salt in a large bowl. Transfer to a sieve set over a medium bowl; let drain for about 15 minutes.Advertisement
Preheat a classic waffle iron to high.
Squeeze the potato mixture, a handful at a time, over the bowl to release excess moisture (don't oversqueeze--some moisture should remain). Pour out the liquid and return the squeezed potato mixture to the bowl. Stir in egg and pepper.
Liberally coat the hot waffle iron with cooking spray. Place a heaping tablespoon of the potato mixture in each quadrant and spread each to a 2-inch-wide circle. Close the lid and cook the latkes until golden brown, 6 to 8 minutes. Repeat with the remaining mixture.
Equipment: Waffle iron (not Belgian-style)