Preheat oven to 200°F (95°C) to keep cooked pancakes warm.
Place grated potatoes in a kitchen towel or cheesecloth and squeeze out as much excess moisture as possible. This step is key for crispy pancakes.
In a large bowl, combine the squeezed potatoes, chopped onion, shredded cheddar cheese, flour, beaten egg, salt, and pepper. Mix until everything is well incorporated.
Heat vegetable oil in a large skillet or frying pan over medium-high heat until shimmering.
Drop about 1/4 cup of the potato mixture into the hot oil for each pancake, flattening them slightly with a spatula to about 1/2 inch thick.
Cook for 3-4 minutes per side, until deep golden brown and crispy. Flip when edges are golden and bottom releases easily.
Transfer the cooked pancakes to a plate lined with paper towels to drain any excess oil.
Keep the cooked pancakes warm in the preheated oven while you cook the remaining batter in batches.
Notes
Squeezing moisture from potatoes is the most crucial step for crispy edges. Keep squeezing until barely any liquid remains.
Don’t overcrowd the pan. Cook in batches of 3-4 pancakes to maintain proper temperature and crispiness.
For extra flavor, add a pinch of garlic powder or paprika to the batter, or swap half the oil with butter when frying.
Store leftovers in airtight container for up to 3 days. Reheat in oven or skillet to restore crispiness, not microwave.