1. Prepare warming oven. Preheat oven to 200° and put a wire rack on a 
baking sheet and place in the oven.
2. Using a box-style cheese grater, grate the onion into a large bowl. Then grate both potatoes into the same bowl, grating down the length of the potato for long strands. Mix the potatoes with the onions as you work to keep them from discoloring.
3. Put potato mixture in a clean dish towel and wring out excess liquid. When fairly dry, put potato/onion mixture back in the bowl and add flour, salt and cayenne then stir in egg. Mix well.
4. Heat a 1/4-inch oil in a large cast iron or heavy skillet over medium heat. Working in batches, spoon about 1/4 cup of the latke mixture into the 
skillet, pressing lightly to form 3-inch pancake. Do not overcrowd the pan. Cook, turning once, until just golden, about 2 minutes per side. Transfer to the rack in the oven while you cook the remaining batter.
5 Serve latkes topped with a small dollop of yogurt horseradish sauce and chopped parsley or scallions.

Per serving: 127 calories, 6g fat, 0g sat fat, 8g carbohydrates, 2g protein, 251mg sodium, 1g fiber