In a large mixing bowl, grate 2-3 russet potatoes. Squeeze out excess moisture. Add cornstarch, salt, black pepper, and green onions. Mix until well combined.

Fold in 1 cup of grated mozzarella cheese until thoroughly integrated.

Preheat a non-stick skillet over medium heat for 2-3 minutes. Drizzle in oil to coat the base.

Drop spoonfuls of the potato-cheese mixture onto the skillet, flattening to ½ inch thick. Cook for 3-4 minutes until golden brown.

Flip each pancake and cook for another 3-4 minutes until both sides are crispy.

Transfer pancakes to paper towels to drain excess oil. Garnish with green onions and serve warm.