Prepare 2 large madeleine pans and generously spray them with baking spray and dust with a tad of flour.
Using an electric mixer, beat eggs with ⅔ cup sugar until blended. Beat in the apple sauce and salt. Add flour and beat just until blended. With the mixer on low speed, gradually add cooled melted butter and beat just until blended.
Spoon 1 1/3 tablespoons batter into each madeleine indentation in pan. Bake until puffed and brown, about 11-13 minutes.
Cool for 5 minutes in the pan and after gently remove them from the pan and place on a serving dish.
In a medium sauce pan over medium heat melt sugar while stirring constantly until a brownish liquid forms.
When sugar has completely melted, add the butter and stir until well combined.
Carefully while still stirring add the heavy cream, once all the cream has been added let the mixture boil without stirring for one minute.
Remove from heat, stir in salt, transfer to a mason jar (or any other container) and let it cool.
Dip madeleines into the caramel sauce, place on a wire rack to harden and sprinkle with sea salt.
In a medium bowl set over a medium saucepan of simmering water, melt the chocolate with the heavy cream, must be well combined. Remove from the heat and set aside. Dip the madeleines into the melted chocolate and place on a wire to harden.