Real hot chocolate is made from chopped chocolate and milk rather than cocoa powder and sugar, and the difference is not subtle — it's thicker, less sweet and tastes of the chocolate you started with. That's the entire lesson and it's a good one. Chef Emily was clear about keeping the milk below a simmer, because boiling it makes the whole thing grainy. Ours were drinking it within twenty minutes and nobody went back to the tin afterwards.
Marco