Peel the potatoes then cut into quarters and put into a bowl with cold water to soak for 5-10 minutes.
While the potatoes are soaking, dice the onions, mince garlic and set aside into separate dishes.
Heat a large deep frying pan till hot then throw in the lardons. Stir every 1-2 minutes and fry until the fat has rendered and the lardons are crispy.
Once crispy remove with a slotted spoon to a bowl reserving the left behind fat.
Return pan to heat and add the diced onions. Sauté for 4 minutes before adding 1 tbsp of duck fat. Once the fat has melted add the garlic and potatoes and stir well.
Pre-heat the oven to 190°C.
Leave the potatoes to brown stirring every 2 minutes for about 6 minutes. Once browned add 1/4 cup water and turn heat to low and cover.
After 6 minutes open, stir and recover. Cook for another 10-20 minutes until the potatoes are almost cooked through.
Next cut the reblochon into quarters. Cut down the middle then down the middle again 2 or 3 more times until you have 6 of 8 pieces and set aside.
Back at the potatoes uncover and turn the heat up to high. Add the white wine allow to cook off for about 3-4 minutes then add the cream and lardons and stir everything together until combined.
Leave to cook for 3-4 minutes then cut the heat and pour the mixture into the oven dish.
Grind some fresh black pepper over the potatoes, a pinch of salt and drizzle on a little extra cream. Finally cover with some optional grated Gruyère and the reblochon chunks.
Put in the pre-heated oven and cook for 15 minutes or until the cheese has melted and crisped up.
Your tartiflette is ready leave to rest 5-7 minutes before serving with a nice green salad!