Chop the chocolate chips finely to ensure even melting.

Place 5 ounces of chopped semi-sweet chocolate in a microwave-safe bowl. Microwave in 15-second intervals, stirring between each until most of the chocolate is melted. Avoid overheating.

Add remaining chocolate and stir until mostly melted and cooled to about 85°F.

Reheat the chocolate for 15 seconds to bring it to a fluid consistency suitable for molding.

Use a brush to coat the inside of silicone molds with a thin layer of melted chocolate. Chill in the refrigerator for 3-5 minutes.

Pop out the chocolate shells carefully. Fill half with hot cocoa mix and mini marshmallows.

Heat a plate in the microwave for about a minute. Lightly melt the rim of each chocolate half.

Press the rims together quickly to seal the sphere. Use melted white chocolate to decorate if desired.

Store in a cool, dry place until ready to serve.