Heat the strawberry preserves with the corn syrup in a saucepan and then press through a fine-mesh sieve into a bowl with the back of a large spoon.
In a stand mixer fitted with the paddle attachment, beat the cream cheese on medium-high speed until smooth. Add the crème fraíche, vanilla, and the
Place a single crepe flat on a serving plate. Using an offset spatula, spread the crepe with a very thin layer of the strawberry preserves. Align another crepe over the first and spread with a very thin layer of the cream cheese mixture. Cover this with another crepe and spread with a thin layer of chocolate custard. Repeat to use the remaining crepes, with the top of the last crepe left uncovered. You should have some strawberry preserves left at this point. Set aside. Cover and refrigerate for at least 4 hours or up to 2 days.
An hour before serving, remove the mille-feuille from the refrigerator. (If the cake is too cold, the confectioners’ sugar will dissolve as the cake warms.) Dust the cake with confectioners’ sugar. Reheat the reserved strawberry preserves and dip the strawberries in them, coating evenly. Garnish the cake with mint sprigs and the glazed strawberries. Cut into wedges to serve.