Potato Tart with Mustard Greens and Lemon Thyme

Preheat the oven to 375°F. Line a 10-inch tart pan with the whole wheat phyllo dough. Leave a 1/2-inch overhang and trim any excess. Place the tart pan on a baking sheet. In a medium mixing bowl, toss the potato slices with the buttermilk and season with salt and pepper. In a large sauté pan, heat the canola oil over medium heat and add the onions. Cook the onions for 2 minutes over medium-high heat. Add the mustard greens to the pan and cook for 5 minutes or until they are wilted. Season with salt and pepper. Shingle half the potato slices on the bottom of the phyllo-lined tart pan. Sprinkle with half of the mustard greens. Repeat the process with the remaining potatoes and mustard greens. In a medium bowl, whisk the eggs, egg whites, and skim milk for 1 minute or until combined. Add the lemon thyme and season with salt and pepper. Pour the egg mixture over the potatoes. Drop teaspoons of the goat cheese around the tart. Bake the tart for 45 to 60 minutes or until it is just set and the potatoes are cooked. Remove from the oven and let sit for 15 minutes before cutting. Cut the tart into 6 pieces and place on a serving plate.