Gather all ingredients.

Beat eggs, flour, baking powder, salt, and pepper together in a large bowl; place shredded potatoes in a clean dish towel and squeeze to remove excess water. Add shredded potatoes and onion to egg mixture and stir.

Heat oil in a large skillet over medium heat. Drop heaping tablespoonfuls of potato mixture into hot oil, working in batches. Flatten slightly by pressing with a spatula.

Cook until golden brown and crisp, about 3 minutes per side.

Transfer to a paper towel-lined plate to drain. You can cover them very loosely with aluminum foil to hold in heat without steaming them.

Repeat with remaining potato mixture. Serve warm topped with sour cream, if desired.