Palmier, AKA elephant ears or butterfly cookies are puff pastry folded with a lot of sugar in-between each layer so that when baked they caramelize and become crispy and flavorful.
Taking it a step further Iground some peanut brittle i made in a robot coup and folded the puff pastry around it.
The peanuts and brown butter gave the toasty puff pastry extra flavor and because the sugar was already at hardball stage I knew they were going to be crunchy.