Wash, peel, and grate the russet potatoes and yellow onion into a large mixing bowl. Drain excess liquid after a few minutes.

In the same bowl, mix the grated mixture with salt, black pepper, flour, and egg until combined into a thick batter.

Heat oil in a large skillet over medium heat until shimmering.

Scoop 2 tablespoons of the batter into the hot oil, flatten slightly, and fry for 3-4 minutes until golden brown. Flip and cook until crispy.

For extra crunch, re-fry each pancake for an additional 30-60 seconds on both sides.

Transfer pancakes to a plate lined with paper towels to absorb excess oil and serve hot with toppings.