Preheat your oven to 200°C (390°F). Start by washing the potatoes thoroughly. Place them in a large pot of salted water and bring to a boil. Cook for 10-15 minutes until the potatoes are tender but still firm. Drain the potatoes and allow them to cool before slicing into 1 cm thick rounds.

In a large skillet, heat 1 tablespoon of olive oil over medium heat. Add the bacon lardons and cook until golden and crisp, about 5-6 minutes. Remove the bacon from the pan and set aside, leaving the rendered fat in the pan.

In the same skillet, add the sliced onions to the bacon fat and sauté for 5-7 minutes until soft and translucent. Add the minced garlic and cook for another 1-2 minutes, making sure not to burn the garlic.

In a large mixing bowl, gently combine the cooked bacon, sautéed onions, and sliced potatoes. Season with salt and freshly ground black pepper. Toss everything together carefully, ensuring the ingredients are evenly distributed but not mashed.

Take an ovenproof casserole dish and rub the inside with a little olive oil or a halved garlic clove for added flavour. Spread half of the potato mixture into the dish, creating a flat and even layer.

Pour half of the crème fraîche or cream over the potato mixture, spreading it evenly to coat the surface. Place half of the Reblochon cheese (cut-side down) on top of the potatoes. Repeat the layering process with the remaining potato mixture, cream, and the second half of the Reblochon cheese.

Cover the casserole dish with aluminium foil and bake in the preheated oven for 20 minutes. Remove the foil and bake uncovered for another 15-20 minutes, or until the cheese is bubbly and golden brown on top.

Once baked to perfection, remove the Tartiflette from the oven and let it rest for 5 minutes before serving. Garnish with freshly chopped parsley if desired. Serve with a crisp green salad or crusty bread to balance the richness of the dish.