Prepare 2 6-cup silicone molds by making sure they are clean and dry.
Put dark chocolate into a microwave-safe bowl. Microwave for 20 seconds, then mix well. Microwave again in bursts of 15 seconds, mixing well after each burst.
When the chocolate starts to melt, use a food thermometer to check your chocolate stays at about 87°F (never go above 90°F).
Microwave again in 10-15 seconds bursts, mixing well after each burst until the chocolate is completely melted.
Using a teaspoon or paintbrush, coat each mold thinly with the chocolate, doing 2 coats. Make sure to pay attention to the edges of the mold, ensuring they are well coated.
Pop into the fridge for 5-10 minutes. Once solid, gently remove the chocolate half spheres from the silicone molds.
Fill 6 of the chocolate half-spheres each with 2 tbsp of caramel flavored hot chocolate mix, mini marshmallows, salted caramel chocolate pieces, and caramel bits as desired.
Take 1 empty half sphere, place rim side down on a warm plate for a few seconds to allow the edge to melt slightly, then press gently over a filled chocolate half sphere to seal them together to form a complete sphere. Repeat until all the spheres are complete.
Drizzle with melted salted caramel chocolate and sprinkles fine bits of caramel and some sea salt flakes if desired.