Line 5"-6" square mold or container with plastic wrap. Set aside.
In a medium heat-proof bowl, whisk heavy cream and Match powder well together.
Add chocolate to the bowl and melt over simmering water at very low heat. Stir to become uniform color.
Pour chocolate into the mold. Refrigerate at least 4 hours.
Slice off the edges, and cut into 1 1/2" squares. Coat the chocolate pieces with Matcha powder, and sprinkle some more over with fine mesh strainer for decoration.