Two-Potatoes Anna

Peel all-purpose and sweet potatoes. Using an adjustable-blade slicer or sharp knife, thinly slice potatoes, keeping sliced white and sweet potatoes in separate piles.

In 10-inch cast-iron skillet with oven-safe handle (or wrap handle with double thickness of foil), heat oil over medium heat. Add onion, cook until tender. Transfer to bowl.

In same skillet, arrange white potatoes, overlapping them slightly. Sprinkle with onion, dot with 2 tablespoons margarine. Sprinkle with 3/4 teaspoon salt and 1/4 teaspoon pepper.

Arrange sweet-potato slices over white potatoes. Dot with remaining 2 tablespoons margarine, sprinkle with 3/4 teaspoon salt and 1/4 teaspoon pepper.

Cook layered potato mixture over medium heat 15 minutes or until bottom layer of potatoes is lightly browned. Meanwhile, preheat oven to 450 degrees F.

Place skillet on bottom rack in oven and bake 25 minutes or until potatoes are tender when pierced with knife, pressing potatoes down with pancake turner occasionally. To serve, loosen edge with pancake turner, carefully invert potatoes onto warm platter. Garnish with parsley sprigs, cut into wedges.