How do you do the gelatin in hot chocolate?
Pour a little cold milk in a mug, (half an inch or so), add the gelatin powder to it (1-2tbsp), let it hydrate and mix it in a little.
Add some sugar to taste and cocoa powder, vanilla extract and a pinch of salt, then slowly pour hot water from a kettle, little by little, while stirring, until you fill the mug.
The hot chocolate should be at a perfect temperature then, but if it isn't just microwave it for 20 sec or so.