The Chocolate Peanut Butter Mousse Tart is one of the most loved tarts in The Pie and Pastry Bible. It was even chosen by Food & Wine for the magazine’s book called Best of the Best. Because my charming friend Marko Gnann doesn’t like peanuts but adores hazelnuts, I created this version, which I dedicate to him. The hazelnut cookie crust is unlike any other. Along with a delicious hazelnut flavor, it is both soft and chewy. It also makes fabulous cookies. The idea for the optional caramelized hazelnuts for the décor was contributed by Beta Baker Matthew Boyer.