A Spanish tortilla, also known as tortilla española, is a traditional dish from Spain made primarily with eggs and potatoes. It is typically cooked in olive oil and can include onions, though this is a matter of personal preference. The ingredients are combined and cooked until the eggs are set, resulting in a thick, round omelet. This dish is often served as a tapa, a small plate of food, and can be enjoyed hot or cold. It is a staple in Spanish cuisine and is popular for its simplicity and rich flavor, making it a favorite among locals and visitors alike.