I have always avoided making chocolate tarts, not out of laziness (I love a bit of pastry-making, in the right mood), but because I have never really felt that the pastry served the chocolate, or was worth the effort here. This is my simple solution: make a base out of chocolate biscuits. And the filling is just as easy to make, too. Not that you’d know from the taste. I never lie about how effortless something is to make, but no one will believe me on this one. I think the hit of salt is…