First, bring a large pot of salted water to a boil. Add your peeled and sliced potatoes, then reduce heat and let them simmer until tender but still holding their shape. This ensures each layer stays distinct in the final bake.
Next, preheat your oven to 425°F (220°C). Sauté bacon in a skillet until it starts to crisp, then remove the rendered fat. Melt butter in the same pan and add sliced onions. Cook until soft and translucent, then deglaze with white wine to lift all those tasty browned bits.
Layer half of your cooked potatoes in a greased baking dish, spread half the bacon‑onion mixture over them, and repeat with the rest. Dollop crème fraîche evenly over this. It adds creamy consistency without overpowering the traditional flavors.
Remove the rind from your Reblochon (if you prefer milder rind flavor). Slice the cheese thinly and spread it evenly on top of your layered dish. Bake until the cheese melts and browns lightly — about 15 minutes — resulting in a bubbly, golden finish.