Line 1-ounce mini muffin tins with paper liners; set aside. Place bittersweet chocolate in a medium heatproof bowl set over a pan of simmering water, and stir until melted. Remove bowl from heat; let chocolate cool about 5 minutes.Advertisement
Pour into a pastry bag and pipe chocolate into liners about halfway full. Garnish with toasted coconut or pistachios. Repeat with white chocolate, first melting as in step 1.
Transfer pan of white-chocolate candies to the refrigerator until set, about 20 minutes. Allow bittersweet-chocolate candies to set at room temperature about 1 hour.
To toast shaved coconut, spread it on a parchment-lined baking sheet, and bake in a 350-degree oven until lightly browned.