Chocolate Leaves for Pistachio-Chocolate Buche de Noel

Gently clean the leaves with a damp paper towel. Let dry on a baking sheet.

Line a baking sheet with parchment paper, and set aside. Heat two-thirds of chocolate in a heatproof bowl set over a pan of barely simmering water until chocolate registers 118°on a candy thermometer. Remove bowl from heat; add remaining chocolate, and stir with a rubber spatula (avoid using a wooden spoon which can impart other flavors)until chocolate cools to 84°. Remove any unmelted pieces; discard, and return bowl to pan. Stir until chocolate reaches 88° to 90°.

Using a pastry brush, paint veiny underside of leaves generously with chocolate, covering entire surface. Place painted leaves, chocolate side up, on prepared baking sheet. Refrigerate the leaves until chocolate is firm, about 10 minutes.

Starting from stem ends, carefully peel leaves from chocolate, and discard leaves. Transfer chocolate leaves to a clean parchment-lined baking sheet, and refrigerate until ready to use.