Preheat the oven to 250
Using a food processor with a coarse grating disc, grate the potatoes and onion
Transfer the mixture to a clean tea towel and squeeze and wring out as much of the liquid as possible
Transfer the drained potato onion mixture into a large bowl.
Add the eggs, flour, salt, baking powder, and pepper, and mix until the flour is absorbed.
Scoop 1/4 cupful of the mixture and tightly pack into thin 3- to 4-inch pancakes. Transfer to a paper towel-lined baking sheet.
Heat 1/4 inch vegetable oil or schmaltz in a large nonstick skillet over medium-high heat.
Working in three batches, fry the latkes until deep golden brown, 3 to 5 minutes per side.
Remove to a rack set on a rimmed baking sheet and sprinkle with salt.
Keep warm in the oven while you make the remaining latkes.