To make the caramel: Using a food processor, pulverize the granulated sugar into fine powder or dust. In a pot, heat the water over medium heat. As the water begins to slowly heat, carefully pour the pulverized sugar into the center of the pot, creating a mound. Do not touch or mix the sugar into the water, let it dissolve on its own. Once the sugar-water begins to boil, keep a close eye on it: in a few minutes the water will boil away and then the sugar will begin to boil. Watch closely, the second the molten sugar begins to turn a light brown or caramel color, take it off the heat and add the whipping cream and butter. Cook's Note: Careful, it will spatter. Whisk the mixture until smooth. Add a big pinch of fleur de sel and whisk to incorporate.
To make the French toast: In a big bowl, combine the eggs, milk, vanilla bean, sugar, and sea salt. Beat these ingredients together. In a frying pan, heat the unsalted butter over medium heat. Dip the bread slices in the egg mixture, turning the bread to coat evenly. Allow the excess egg mixture to drip back into the bowl and add the bread to the hot butter. Fry the bread for about 1 minute per side, or until golden. Turn the heat down to medium low and cook for 1 to 2 minutes on each side. Repeat as necessary.
Serve the French toast in stacks slathered with caramel and topped with a dollop of creme fraiche.