Spanish Pumpkin Omelet (Tortilla de Calabaza)

Heat large saucepan of water over high heat to boiling; add pumpkin. Cook until crisp-tender, about 12 minutes. Remove pumpkin to colander; drain well on paper toweling.

Heat 3 tablespoons of the oil in 10-inch ovenproof skillet over medium-high heat until fragrant. Add onion, ham, and pumpkin; cook until onion is soft, about 5 minutes. Remove skillet from heat; cool to room temperature, about 10 minutes.

Beat eggs, water, and salt in medium bowl until frothy. Add pumpkin mixture; stir until well mixed. Wipe skillet clean.

Heat oven to 350F.

Heat remaining 2 tablespoons oil in clean skillet over medium-high heat until rippling. Add egg mixture to skillet; reduce heat to low. Cook, shaking pan gently and frequently to prevent sticking, until bottom of mixture is set but top is still slightly runny, about 10 minutes. Transfer skillet to oven; bake until top of omelet is set but not dry, about 4 minutes. Transfer to heated round platter; serve immediately.