Preheat oven to 400°. Heat a 17- x 10-inch cast-iron pan or 12-inch cast-iron skillet in oven 10 minutes. Toss together sweet potato wedges and next 5 ingredients in a large bowl. Place sweet potato mixture in hot pan.
Bake at 400° for 25 minutes. Stir once, and bake 15 more minutes or until potatoes are tender and begin to caramelize.
Spoon potato mixture over mâche; drizzle with Citrus Vinaigrette.