Place the grated potatoes in a clean kitchen towel and squeeze out as much moisture as possible. Transfer the drained potatoes to a mixing bowl.
Add the chopped onion, egg, flour, salt, pepper, and garlic powder (if using) to the bowl. Mix until well combined.
Heat the vegetable oil in a large skillet over medium heat.
Once the oil is hot, drop spoonfuls of the potato mixture into the skillet, flattening them slightly with the back of the spoon. Fry for about 3-4 minutes on each side, or until golden brown and crispy.
Remove the pancakes from the skillet and place them on a paper towel-lined plate to drain excess oil.
Serve warm with sour cream or applesauce.