Using a small pastry brush, coat underside of each leaf with a thick layer of chocolate. (If chocolate drips onto top of leaf, gently wipe away with your finger.)
Drape leaves, chocolate sides up, over handle of a wooden spoon set on a parchment-lined baking sheet. Refrigerate until set, about 10 minutes.
Gently grasp chocolate layer of each leaf with kitchen tweezers. Holding stem, peel off mint leaf. Store, refrigerated, in an airtight container for up to 2 days.