Totally accidental, totally delicious. This is a recipe for Real Cooks, who measure everything by eye and stuff anyway.
Make a bunch of spaghetti. Keep re-using the water for about 3 batches (don't worry, you'll eat it in the next couple of days, anyway), until you have thick pasta water.
Stir in cocoa powder and cinnamon and sugar.
AMAZING! Smooth, the tiniest ice crystals, rich.