Hot Gianduja “Chocolate Fondant” with Red Grapefruit Marmalade

Gianduja (pronounced zhahn-doo-yah), refers to the combination of chocolate and hazelnuts. This is probably the best—and richest—version of the currently popular warm individual chocolate cakes that are still runny inside (the “fondant”). Ken serves them on a big white rectangular plate with a little mound of grapefru