Add some water to your kettle or saucepan and let it come to a boil while you make the rest of the drink. (Fill to the minimum fill line if there is one.)
Measure and add caramel syrup, rye whiskey and chocolate bitters to the cocktail serving glass.
Add one ounce of the now-boiling water to the glass. You can measure in a heatproof measuring cup if you like.
If you are using cocoa, use the mini sieve (sifter) to sprinkle it onto the top of the cocktail.
Give the cocktail a quick stir so the cocoa powder will mix into the drink.