Bring whipping cream to a simmer in a small heavy saucepan over medium heat. Remove from heat; add white chocolate, butter, and grapefruit rind, stirring until smooth. Pour white chocolate mixture into a small metal bowl; cover and chill 2 to 3 hours or until firm.
Shape white chocolate mixture into 1 1/4" balls (about 1 tablespoon); cover and chill truffles 8 hours or until firm.
Melt vanilla bark according to package directions. Cool. Dip truffles in coating; place on wax paper. Sprinkle with thyme leaves while coating is wet. Let stand until firm. Store truffles in refrigerator.
* Use good quality white chocolate for truffle making. You'll taste the difference.
* Citrus and fresh herbs are a nice flavor pairing. To get fine grapefruit rind, use a Microplane grater.
* Fresh thyme leaves look festive sprinkled onto these candies. To remove leaves easily, just strip them from the woody stem (no chopping needed).
* Use a cookie scoop to shape truffle balls evenly.