1. Wash and peel the potatoes, then grate them into a large bowl using the coarse side of a box grater. Grate the zucchini and onion into the same bowl.
2. If there is excess liquid, drain as much as possible from the mixture.
3. Add a pinch of salt, pepper, flour, and egg to the mixture. Combine thoroughly to create a thick batter.
4. Heat 1-2 tablespoons of vegetable oil in a large skillet over medium heat. For each pancake, scoop about 2 tablespoons of batter into the skillet, flattening with the back of a spoon or spatula.
5. Fry the pancakes for 3-4 minutes per side until they are deeply golden brown and crispy. Transfer them to a paper towel-lined plate.
6. Once all pancakes are fried once, return them to the skillet for an additional 30-60 seconds per side for extra crunch.
7. Serve immediately while hot and crispy. Top with your choice of applesauce, sour cream, or yogurt sauce.