Spanish Potato Omelette (Spanish Tortilla)

Bahan-bahan (12 porsi)

• 1/2 cup olive oil
• 5 potatoes (diced into 1-inch pieces)
• 1 brown onion (chopped)
• 8 eggs
• 1 pinch salt (to taste)
• 1 pinch cracked pepper (to taste)
• 1 pinch parsley (to garnish, optional)