Combine the condensed milk with the honey and butter, simmer over a low heat for approx. 30 mins, stirring constantly until the mixture turns a caramel colour. Pour into the prepared tin, leave to cool, cover and chill for approx. 2 hrs. Cut the caramel into approx. 2 cm cubes.
Pour the cake glaze into a bowl. Dip the caramel squares in the cake glaze, let the excess chocolate drip off, place on a cooling rack for approx. 1 min., then transfer to a sheet of baking paper. Sprinkle immediately with fleur de sel, cover and chill for approx. 2 hrs.