Prepare 9 x 13-inch baking pan with bakers choice spray or butter. Line bottom of pan with parchment paper. Lightly spray parchment paper with bakers choice or lightly butter; set aside.
Preheat oven to 350 degrees.
In a medium bowl; whisk together flour, salt and cocoa powder; set aside.
Place chocolate and butter in bowl of double boiler. Set over simmering water, stirring occassionally until completely mealted and combined. Turn heat off and leave bowl over hot water; add both sugar and brown sugar. Whisk until completely combined. Remove bowl from hot water. it should be room temperature. If not, allow to cool a few minutes.
When chocolate is at room temperature; add three eggs and whisk just until combined. Add remaining two eggs and whisk just until combine. Add vanilla and stir until combined being care to not overbeat batter at this point or you will have a dry brownie.
Gently fold dry ingredients into chocolate mixture, again do not over mix. NOTE: All this mixing is done by hand.
Spread 1/2 of the brownie mixture in bottom of prepared pan. In a zig zag fashion, drizzle/pour caramel over brownie mixture (this mixture is thick), taking care to not allow the caramel to touch sides of pan as it will burn. Spread evenly over brownie mixture, again ensuring caramel does not touch pan. Drop heaping spoonfuls of remaining brownie mixture over caramel mixture; spread evenly over caramel mixture to edges of pan.
Bake for 30 to 35 minutes. Top with begin to look like it's drying out a little around the edges when done. Remove from oven. Sprinkle top of brownies with 1 1/2 tsp Fleur de Sel and 1 tsp coarse sugar.
Allow browines to completely cool before cutting. Store wrapped in plastic for up to 4 days.