Misutgaru began as travellers' food, a powder of roasted grains that kept for weeks and could be stirred into water on the road. Today it is the drink of Korean summer: mothers shake it with cold milk for breakfast before school, office workers buy it as misutgaru latte from cafés, and farmers drink it at midday in the fields of July. The powder is a mix of roasted barley, glutinous and brown rice, black and yellow soybeans, and sesame, and it tastes of toasted cereal and peanut, lightly sweet, with a thick, creamy body that fills you up like a light meal. The common mistake is tipping the powder into a full glass of milk and stirring: it floats, clumps into dry balls and never fully mixes. Shake it in a jar with a little liquid first, or blend it, then add the rest. It is ready when the drink is smooth, beige and frothy with no dry flecks, and slightly thickened after a minute's rest. Use water or soy milk for a dairy-free version, and note that the barley means it is not gluten free. Chef's tip: a pinch of salt makes the grain flavour taste rounder and less flat.