Bring a small pot of water to a boil.
Place chocolate into a heat-proof bowl and set it over the hot water. Stir frequently with a spatula until the chocolate is mostly melted.
Remove the chocolate from the heat. The residual heat in the mixture will finish melting the final pieces.
Spoon your chocolate into your bomb molds, following the mold's specific instructions for how much to fill it.
Place your molds into the freezer for about 15 minutes.
To create the hot cocoa mix, combine the powdered sugar, cocoa powder, pumpkin pie spice, and salt in a bowl. Stir thoroughly.
Remove the bomb molds from the freezer.Fill half the molds with the cocoa powder. Typically, this is about 2 tablespoons of mix per bomb.
Heat a plate in the microwave for about 20 seconds. It should be warm to the touch.
Press one of the empty chocolate mold halves into the plate for about 5-10 seconds. The rim should begin to melt.
Press the warm half into one of the filled halves. If needed, dip your finger into any leftover heated chocolate and rub the seam for a secure connection.
Freeze the cocoa bombs for at least 5 minutes to firm.
To make your hot cocoa, add your hot cocoa bomb to about 1 ½ - 2 cups hot milk and stir. The outer chocolate will melt and release the inner mix. Top with whipped cream, sprinkles, and/or marshmallows.
