Directions

1. Preheat oven to 400 degrees. Arrange potatoes on a rimmed baking sheet. Drizzle with 1 tablespoon oil; season with salt and pepper. Roast until tender and golden brown, about 30 minutes. Set aside.
2. Preheat broiler. Whisk eggs, mustard, 1/2 teaspoon salt, 1/4 teaspoon pepper, and the hot sauce in a large bowl; set aside.
3. Heat butter and remaining 2 tablespoons oil in a large cast-iron skillet over medium heat until butter has melted. Add leeks; cook, stirring, until soft, about 5 minutes. Add ham; cook, stirring, until heated through, about 2 minutes.
4. Add egg mixture, and gently stir with a heatproof rubber spatula. Cook, using spatula to pull eggs away from sides, allowing uncooked egg to run underneath, until almost set, about 8 minutes.
5. Arrange potatoes over top of frittata. Broil frittata until set and lightly golden, 30 seconds to 1 minute. Serve, cut in wedges, warm or at room temperature.