Using a funnel and four 4-ounce mason jars, layer the ingredients in each jar as follows: 1 tablespoon granulated sugar, a pinch salt, 2 tablespoons cocoa, 2 tablespoons instant dried milk, 1 tablespoon shaved semisweet chocolate and 12 mini marshmallows. Seal the jars.
To serve: Tip the hot chocolate mix from 1 jar into a mug and top up with 1 cup boiling water. Mix.