Robiola Bosina or Brie can be substituted for the Reblochon-style cheese.
Preheat oven to 375 degrees. Butter a shallow 2-quart casserole. Cover potatoes with water in a medium saucepan and bring to a boil. Season with salt; cook until potatoes are tender, about 10 minutes. Drain.
Meanwhile, cook bacon in a large skillet over medium heat, turning, until crisp and golden, about 12 minutes. Transfer to a plate; pour off all but 1 tablespoon fat from skillet. Add onion; cook over medium heat, stirring occasionally, until lightly caramelized, about 15 minutes. Add wine and cook until reduced, about 2 minutes. Stir in bacon.
Arrange half of potatoes in prepared dish. Season with salt and pepper. Top with half of bacon mixture and half of cheese. Repeat with remaining ingredients. Bake until cheese is bubbling, about 25 minutes; serve.