Melt chocolate in top of a double boiler over hot water.
Line a baking sheet with aluminum foil, pour chocolate onto baking sheet.
For rippled chocolate hearts, gently shake baking sheet until chocolate is level and about 1/4 inch thick.
Let chocolate cool 5 to 10 minutes.
Gently run a metal decorating comb over chocolate to achieve a rippled effect and to flatten chocolate to about 1/8-inch thickness.
Let stand until chocolate is firm.
Firmly press a 1-inch heart-shaped cutter into chocolate, cutting through chocolate completely.
Lift cutter up, and remove cutout by gently pressing through cutter with a small wooden utensil. (Fingers leave prints.)
Cut 12 chocolate hearts.
Break remaining chocolate into small pieces.
Shave edges of chocolate with a vegetable peeler, holding chocolate with paper towels so that heat from hand doesn't melt chocolate.