1/2 cup melted butter
1 (0.6 ounce) square unsweetened chocolate
2/3 cup confectioners' sugar
2/3 cup white sugar
2 cups frosting
Heat oven to 375 degrees F (190 degrees C). Line baking sheets with parchment paper.
Place butter in a large bowl and beat cream until fluffy. Stir in chocolate and confectioners' sugar. Beat until smooth. Stir in white sugar. Make a well in center of cream and pour sugar mixture into well. Scrap parchment paper from sides of pans. Press 1/3 cup cream onto parchment paper. Press remaining 1/3 cup cream mixture onto parchment paper. Shape into 1/3 inch squares. Place 2 inches apart onto baking sheets.
Bake 10 minutes in the preheated oven. Remove from baking sheet to wire rack. Cool and frost squares, place 2 inches apart onto parchment paper. Spread frosting over cream layers. Place 2 inches apart onto parchment paper. Cool completely. Cut into squares.