Measure out 180 grams of cold water. Begin to whisk the water and add in 30 grams of unflavored gelatin while whisking. Set aside.
Add sugar, corn syrup, and water in a heavy duty, thick bottomed pot.
Stirring constantly, cook until syrup reaches 252F.
Turn off heat. Pour syrup into a 5 quart planetary mixing bowl and allow it to cool undisturbed until mix reaches 212F.
While syrup is cooling, heat gelatin over a hot water bath until fluid.
Once syrup is 212F, add in gelatin. Using the wire whisk attachment, turn mixer to high. Mix for 8 minutes. Add in cocoa, mix for 30 more seconds.
Spread marshmallow directly on top of chocolate caramel.
Top marshmallow with a lightly oiled piece of parchment paper and allow it to set for a minimum of 12 hours before cutting.
Cut into desired size. Wrap pieces in cello candy wrap or cut parchment.
Store in an airtight container.