Use Dutch-process cocoa — natural cocoa is too sharp. Whisk into cold liquid or add slowly to hot liquid while whisking — don't dump into boiling liquid. Pull off heat when slightly loose — thickens in the bowl. Stir in butter at the end for extra richness. Cocoa clumps in humidity — shake before measuring. Sugar-free: substitute allulose 1:1. Keeps 6 months sealed in cool dry pantry.