Preheat the oven to 375 degrees F. Heat the olive oil in a 10-inch ovenproof nonstick skillet over high heat. Add the potatoes, onion, 1 1/2 teaspoons salt, and pepper to taste. Cook, turning occasionally, until the potatoes are tender, 10 to 12 minutes. Meanwhile, beat the eggs in a large bowl until foamy.

Set a colander in another large bowl and transfer the cooked potatoes, onion and cooking oil to the colander. Toss gently to drain as much oil as possible; reserve the oil in the bowl. Add the potatoes and onion to the eggs, making sure they are submerged.

Heat 1 tablespoon of the reserved cooking oil in the skillet over medium-high heat. Add the potato-egg mixture and press evenly into the pan with a rubber spatula. Cook until the underside is golden brown, about 4 minutes. Transfer to the oven and bake until set, about 8 more minutes. Loosen the edge of the tortilla with the spatula, then invert onto a plate. Season with salt. Cut into wedges.

Toss the parsley with the piquillo peppers, 1 tablespoon of the reserved cooking oil, the lemon juice, and salt and pepper to taste. Serve with the tortilla.

Per serving: Calories 441; Fat 24 g (Saturated 4 g); Cholesterol 215 mg; Sodium 876 mg; Carbohydrate 48 g; Fiber 4 g; Protein 12 g

Photograph by Antonis Achilleos