1. Preheat your oven to 400°F or 200°C.

2. Cook diced bacon in a large skillet over medium heat until it reaches a crispy texture. Remove the skillet from the heat and set the bacon aside.

3. Using the same skillet, add more butter if necessary, then sauté sliced onions and minced garlic until they are caramelized and golden brown.

4. Boil sliced potatoes in a separate pot of salted water for 10 minutes, or until they are slightly tender. Drain the potatoes and set them aside.

5. Grease a 9x13-inch baking dish and create a layer of potatoes. Add a layer of caramelized onions, crispy bacon, and a sprinkle of salt and pepper on top. Repeat this process until all ingredients are used, finishing with a layer of potatoes on top.

6. In a small bowl, whisk together 250ml or 1 cup of heavy cream, 125ml or 1/2 cup of crème fraiche (or sour cream), and 60ml or 1/4 cup of white wine. Pour the mixture evenly over the potato layers.

7. Top the dish with sliced cheese, ensuring the entire surface is covered.

8. Cover the dish with aluminum foil and bake for 30 minutes. Remove the foil and continue baking for an additional 15-20 minutes, or until the top is golden brown and the potatoes are tender.

9. Garnish with fresh parsley and serve hot.