Preheat oven to 425ºF and line a baking sheet with a silicone mat.
Generously butter the inside of 2 (5 ½ oz. each) ramekins; set aside.
In a medium mixing bowl, combine egg yolk, egg and sugar. Whisk until the mixture is light with a lemon colored and foamy; set aside.
In a double boiler, place chocolate and butter; cook until melted, stirring occasionally, about 2 minutes.
Pour chocolate mixture into the egg mixture and whisk until well combined.
Add cocoa powder to the egg mixture using a fine sieve over top and tap or rub a spoon until the powder has passed through; stir until combined.
Repeat the same method with flour; stir until mixed.
Add fleur de sel and stir until all the ingredients are very well combined.
Fill up each ramekin with batter to about 1/3rd. Spoon caramel sauce in each and cover with the rest of the batter.
Place the ramekins on the prepared baking sheet. Transfer to the preheated oven and bake for 12 minutes.
Remove from the heat and let them rest for 4 minutes.
Loosen the edges from the ramekin with a knife.
Invert each cake onto a serving plate and dust with confectioners’ sugar; garnish with raspberries and serve immediately.