Melt chocolate and coconut oil in a double boiler, stirring constantly until mixture reaches 115°F (46°C) on candy thermometer. Remove from heat and continue stirring until temperature drops to 84°F (29°C) for proper tempering.

Using a pastry brush, coat the inside of each silicone sphere mold cavity with a thin, even layer of tempered chocolate. Ensure complete coverage with no thin spots. Refrigerate for 5 minutes until set.

Apply a second coat of chocolate to strengthen the shells, brushing in the opposite direction from the first coat. Refrigerate for another 5 minutes until completely firm and easily releases from molds.

In a small bowl, whisk together cocoa powder, maple syrup, vanilla extract, and sea salt until smooth and well combined. The mixture should be slightly thick but pourable.

Carefully remove chocolate half-spheres from molds by gently pressing on the bottom. Handle with clean, dry hands to avoid fingerprints on the chocolate.

Fill 6 half-spheres with 1 teaspoon of hot chocolate mix, 4-5 mini marshmallows, and a pinch of crushed freeze-dried fruits if using. Do not overfill.

Warm a clean plate or griddle over low heat for 30 seconds. Gently press the rim of empty half-spheres onto the warm surface for 2-3 seconds to slightly melt the edges.

Immediately press the warmed half-sphere onto a filled half-sphere, rotating slightly to seal the seam completely. Hold for 10 seconds until set.