1. Preheat the oven to 400 degrees. Spray a 2-quart baking dish with vegetable cooking spray.
2. Melt butter in a large skillet over medium heat, then add onions. Cook and stir until onions are soft and just beginning to brown, about 10 minutes. If onions darken too quickly, reduce heat slightly. During the last minute of cooking, stir in the garlic.
3. While the onions cook, slice potatoes lengthwise into 1/4-inch slices. Add to a mixing bowl and toss with oil; then add salt and pepper and mix well.
4. Place a third of the potatoes in an even layer in the bottom of the baking dish. Top with half the onions, a second third of the potatoes, the remaining onions, then the remaining potatoes.
5. Bake until the potato layers are tender and the top is lightly browned, about 45 to 50 minutes.
6. Allow to rest for 5 minutes before serving. If desired, garnish with parsley. Serve hot or at room temperature.
Source: Hannaford fresh Magazine, March - April 2012