Shred enough potatoes to make 4 cups. Rinse well and pat dry.
In large bowl, mix potatoes, onion, salt and pepper. In 10-inch nonstick skillet, heat 1 tablespoon of the oil over medium heat. Pack potato mixture firmly in skillet, leaving 1/2-inch space around edge
Reduce heat to medium-low. Cook about 15 minutes or until bottom is brown. Drizzle oil evenly over potatoes. Cut potato mixture into fourths; turn over. Cook about 12 minutes longer or until bottom is brown.