Prep Potatoes & Onions: Start by peeling and grating the 4 medium potatoes. Once grated, place them in a clean towel and squeeze out as much moisture as possible. This step is crucial for achieving crispy pancakes. After removing the moisture, combine the grated potatoes with 1 finely grated or chopped medium onion.
Mix Batter: In a large mixing bowl, combine the potato-onion mixture with 1 large egg, 1/4 cup all-purpose flour, 1 tbsp of cornstarch (if using), 1 tsp salt, 1/4 tsp black pepper, and any optional seasonings like 1/4 tsp garlic powder or 1/2 tsp dried thyme or parsley. Mix thoroughly until the batter is thick but moist.
Heat Oil: In a large skillet, pour enough vegetable oil to cover the bottom, heating it over medium-high heat. To test the oil, drop in a small spoonful of the batter; if it sizzles, the oil is ready for frying.
Fry Pancakes: For each pancake, scoop about 2 tablespoons of the mixture into the hot oil. Flatten it gently with a spatula. Fry the pancakes for about 3-4 minutes on each side, or until they are golden brown and crispy. If you want a perfectly crisp texture, avoid overcrowding the pan.
Drain and Serve: Once cooked, place the pancakes on a plate lined with paper towels to absorb excess oil. Serve hot, with sour cream or applesauce, and feel free to get creative with additional toppings like smoked salmon or fresh herbs!