Line a small baking sheet with foil and chill.
In the top of a double boiler, or in a small metal bowl set over a saucepan of barely simmering water, melt the chocolate, stirring occasionally until smooth. Stir in 2 teaspoons of the ginger and spoon onto the center of the baking sheet. Spread with a rubber spatula into a rough rectangle and sprinkle with the remaining 1 teaspoon of ginger, pressing lightly to help adhere.
Chill until firm, about 30 minutes, then break into triangle-shaped pieces (shards).
Yield: garnish for 2 brulees