In a large nonstick skillet, heat oil over medium-high heat. Add potato and onion and saute until potato is almost tender, about 10 to 12 minutes.
In a medium bowl, whisk together the eggs, cream, salt, and pepper. Stir in the cheddar cheese, Parmesan cheese, and ham. Pour into skillet, reduce heat to medium and cook, without stirring, until set around the edge but still runny in the center, about 5 minutes.
Place skillet under broiler, and broil until golden brown and just set, about 2 minutes. Sprinkle with chives. Loosen edge with a rubber spatula, slide onto a serving plate, and cut into wedges.
409 calories (22g protein, 15g carbohydrate, 29g fat) per serving