Place chocolate in a medium bowl. Bring heavy cream and bourbon just to a simmer in a saucepan over medium. Remove from heat, and pour cream mixture over chocolate. Let stand 1 minute; stir vigorously until cream and chocolate are thoroughly blended. Let mixture cool 15 minutes. Cover with plastic wrap, and chill until firm, about 2 hours. (If you cannot make the truffles immediately, the mixture will keep, covered, in the fridge up to 1 week.)

Place chopped pecans on a shallow plate. Line a baking sheet with parchment paper.

Working quickly and using a small warmed teaspoon (dipped into hot water and then dried), scoop chilled chocolate mixture by 2-teaspoon portions, and shape each into a ball. Place each ball on chopped pecans. Once the plate is filled, wash hands and roll balls in pecans to completely cover. Transfer balls to a parchment paper-lined baking sheet. Repeat with remaining chocolate mixture and pecans.

Chill balls until firm, about 1 hour. (Or freeze until firm, about 10 minutes.) Enjoy them now, gift them, or store in an airtight container in the refrigerator up to 1 week.