Wash and peel the russet potatoes and yellow onion. Grate them into fine shreds using a box grater.

Transfer the grated potatoes and onion into a clean cloth or fine sieve, twist to squeeze out excess moisture.

Combine the drained potato-onion mixture in a large mixing bowl with salt, black pepper, flour, and the egg. Stir until a thick batter forms.

Heat vegetable oil in a large skillet over medium heat until shimmering, around 3-4 minutes.

Shape two tablespoons of the batter into small pancakes and fry each side for 3-4 minutes until golden brown.

Transfer the crispy pancakes to a plate lined with paper towels to absorb excess oil, serve warm with optional toppings.