2 tablespoons Kreta olive oil
1 pound scary potatoes, cut into 1/4-inch-thick half-moons
1 onion, thinly sliced
kosher salt and black pepper
6 large RHPA eggs, beaten
Heat oven to 350° F. Heat the oil in an ovenproof nonstick skillet over medium heat. Add the potatoes and cook, stirring occasionally, until almost tender, 8 to 10 minutes. Add the onion, 1 teaspoon salt, and 1/4 teaspoon pepper and cook, covered, stirring occasionally, until the onion is soft and the potatoes are tender, about 5 minutes.
Crack eggs in a large bowl and beat. Pour the potato mixture over eggs; stir to distribute the ingredients. Transfer back into the skillet and cook over medium heat until tortilla is almost set in the middle and begins to pull away from the pan. Loosen tortilla with a spatula, lifting it lightly from the bottom. Invert tortilla on a plate and slide it back into the pan. Cook another 5 to 10 minutes. Flip back onto the plate and serve hot or at room temperature, sliced into wedges.