6-inch fillable ornament, 6-inch (15 cm) available at craft and baking stores or online
Melt the milk chocolate in the microwave in 20-second intervals, stirring until smooth.
Open the fillable ornament and coat the inside with a lightly oiled paper towel. Pour the melted chocolate into one of the halves. Close the ornament, rotating the ball so that the chocolate evenly coats the entire surface. Continue slowly rotating for 5 minutes. You may have to shake it a bit to get the chocolate to fill any holes. Place the ball in the freezer, then flip it after 2 minutes. Continue to flip it every few minutes, 2-3 more times. The chocolate should be set by then. Freeze for 30 minutes.
Remove the ball from the freezer. Carefully open the ornament and remove the ball. Work quickly and avoid touching the ball for too long with your warm hands. If you want to be extra careful, immediately after unmolding, place the ball back in the freezer for a few minutes.
Dip or run a flat-bottomed bowl in boiling water, then dry the entire bowl. Invert the bowl onto a flat surface, then place one side of the frozen chocolate ball on the hot bowl.
Twist back and forth with a gentle motion, making sure that you’re not applying too much pressure to the ball, as it is very fragile. Use a paper towel to help insulate the ball from your warm fingers. You may have to reheat and wipe off the bowl a few times as it will cool down a bit. Place the ball back in the freezer.
On a large plate, stack the brownies on top of each other, then surround them with berries. Place a scoop of ice cream on top of the brownies, then slowly place the chocolate ball on top. To cover up any holes or imperfections along the seam where the ball touches the plate, surround the base of the ball with more berries.
Microwave the dark chocolate with the heavy cream in 20-second intervals until smooth and glossy.
Pour the chocolate sauce over the ball in a circular motion.