Place heavy cream and butter in a small saucepan and bring to a boil. Meanwhile, in a larger saucepan place sugar and corn syrup. When the cream/butter mixture is boiling, add the fleur de sel, stir, then strain into a bowl and set aside. Meanwhile the sugar/corn syrup mixture should be in the early stages of melting and turning to caramel. Gently move the darker, melted parts of the sugar around the pot, so everything cooks to the same consistency. Bring the caramel to an amber color until a thermometer registers 145 degrees C (and up to 160 degrees C), then turn off the heat and add the cream/butter mixture, a little bit at a time (the mixture will bubble up). Turn on the heat and cook to 120 C degrees. Turn off the heat, remove the thermometer and pour the caramel into a baking sheet lined with parchment paper. Cool to room temperature, about 2 hours.
When caramel is cool, remove from the pan. Using a small paring knife go around the edge and flip over onto parchment paper sprayed with non-stick spray. Give it a quick tap and when it comes out remove the parchment paper. Cut into small pieces (about 5 dozen) using a knife or scissors. Place a caramel in the middle of a wrapper, wrap and twist the ends.