I got the recipe for this cupcake from Pusiva's Culinary Studio
. I have reprinted the recipe below. The only change from the original was to add the fleur de sel. A VERY important point about this recipe is that it did not state how many cupcakes it would make. As it turns out it, it only made 6 cupcakes. Definitely double it if you would like more than 6.
I got the salted caramel frosting recipe from Vanilla Garlic
. He used it on Apple Cardamom cupcakes
which make me drool just looking at them.