In a food processor or on a box grater, coarsely shred the potato and onion. For longer strands, lay the potato sideways in the chute of your food processor.
Transfer grated mixture to a bowl lined with a fuzz-free dishcloth (linen is great here) or cheesecloth.
Pull up the sides of the cloth, forming a bag of grated ingredients, and twist it until you’ve squeezed out all of the excess liquid. Let stand for 1 to 2 minutes, then squeeze out one more time.
Heat oven to 350. Lightly oil a large baking sheet and set aside.
Discard the liquid in the bowl, then add wrung-out shredded potato and onion to it.
Sprinkle baking powder, salt, and several grinds of black pepper over mixture and stir with a fork until it distributes throughout the shreds.
Add flour, and again, stir into the potato-onion mixture until the pieces are evenly coated.
Crack eggs on top; use your fork to break up the yolks and stir them so that they’re evenly distributed through the batter.
Heat your waffle iron to high heat. Once hot, coat lightly with a nonstick spray.
Heap some latke mixture on top and spread it into an even layer. Cook until the latkes are a nice, deep golden brown underneath.
Transfer to oiled baking sheet, paler side down, and place in warmed oven. Continue with remaining latke batter.
Keep latke waffles in oven until crisp (about 5 to 10 minutes), or until all the other parts of your meal are ready.
Serve with applesauce or sour cream, latke-style, or breakfast-style, with eggs and bacon. Chives make it pretty.