After heating several ounces of chocolate in a double boiler, pour a thick layer of the melted chocolate onto a non-stick surface, such as a silicon mat or waxed paper. Use a teacup or cookie cutter or biscuit cutter, and score the softened chocolate to the size that will fit into your parfait glass before it hardens completely.
When it does harden, use a sharp paring knife and carefully trim away the edge.
Add another layer of melted chocolate on top of the first if it seems too thin, and make more disks than you need in case some become broken.
"Food is our common ground, a universal experience." - James Beard