Set oven rack to the middle and preheat to 400 degrees Fahrenheit. Take a 9×13 baking dish and spread 1-2 Tbsp of the melted coconut oil in the bottom of the pan. Set aside.
Wash, but do not skin, your potatoes. Cut them into roughly 1/4″ slices and arrange them in one layer in the baking dish. Brush the other 1-2 Tbsp coconut oil over the tops of the potatoes. Sprinkle with 1-2 pinches of fleur de sel. Bake for 20 minutes.
After 20 minutes have passed, flip the potato slices. Sprinkle with another 1-2 pinches of fleur de sel and return to the oven for another 20 minutes. Leave on the middle rack and broil for 5 minutes or so. Serve immediately.