Change out of your white shirt, if you are wearing one, to avoid getting purple sweet potato juice on your clothing.
Preheat an oven to 200°F to keep the pancakes warm as you make the batch.
Peel the sweet potatoes. Then using a box grater, grate the sweet potatoes and onions, putting them into a strainer over a bowl as you do. Mix the onion around a bit to try to prevent the purple from discoloring.
1½ pounds sweet potatoes, ½ medium sized onion
Once you have grated all of the sweet potato and onion, squeeze with paper towels or cheesecloth to get rid of as much moisture as you can.
In a medium to large bowl, mix the sweet potatoes and onions with the flour, salt, baking powder, and pepper. Then add the eggs and mix.
¼ cup all purpose flour, 1 teaspoon salt, 1 teaspoon baking powder, ¼ teaspoon black pepper, 2 eggs, lightly beaten
Heat a thin layer of oil in a griddle or frying pan. When hot, add large scoops (I used a large cookie scoop) of potato mixture and flatten them slightly. Fry for 2 to 3 minutes and then flip and fry the second side.
neutral vegetable oil, for light frying
Place cooked pancakes in a single layer on a baking sheet and move to the oven to keep warm until ready to serve.