* ¼ cup olive oil
* 1 large Spanish onion, chopped
* 3 yellow-fleshed potatoes, peeled and thinly sliced with a mandoline
* 10 eggs, lightly beaten
* Salt and pepper
1. In a large non-stick skillet over medium-high heat, cook the onion and potatoes in the oil, stirring frequently until well browned, about 10 minutes. Season with salt and pepper. Let cool. With the rack in the middle position, preheat the oven to 180°C (350°F). 2. In a bowl, gently combine the eggs and the potato mixture. Season generously with salt and pepper. Line a 20-cm (8-inch) square Pyrex baking dish with parchment paper, allowing the paper to hang over 2 opposite sides. Oil the other 2 sides. Pour the egg mixture into the dish and transfer to the oven. Bake until the omelette is slightly puffy and the centre is set (about 45 minutes). Let cool for about 10 minutes. Remove from the dish and cut into bite-size squares. Arrange on a platter and serve with toothpicks. Serve cold or at room temperature. 3. Note: To vary the flavour, add chopped herbs, cooked and drained bacon, or grated cheese.