11: Add half the onions-bacon mixture, salt and pepper.
12: Cut remaining potatoes slices to make a second layer.
13: Add 1 Reblochon, salt and pepper.
14: Cut 1 Reblochon in half across the middle, then vertically. Note : You can, before cutting them, wash cheese crust under the tap with a brush, even remove crust if you don't like it. Put cheese quarters on potatoes, and put in the oven for about 30 minutes.
15: Your tartiflette is ready when cheese is melted, and crust is crispy.
Remarks
I think it's good too with other cheeses like St. Nectaire farmhouse or Mont d'Or, but of course this is not a "true" tartiflette. Is this a true one? Not really says Julie (born in the region) who tells me that the potatoes should be fried in a pan before going in the dish. Nathalie, from Bellegarde, on the other hand, doesn't cook the potatoes, she just puts them into cold water and stops when they come to the boil. Well, as you see, one recipe but many versions... All the proportions indicated can be easily changed according to taste.