Toast marshmallows over stove top until golden. Let cool.

In a small pot, bring half-and-half to a boil, then pour it over chocolate in a bowl and stir until chocolate has melted.

Return chocolate mixture to the pot and whisk in the milk.

Over medium heat, bring to a simmer and stir in 1/2 cup amaretto.

Pour remaining amaretto into a small bowl; place graham-cracker crumbs on a saucer.

To assemble:

Dip the rims of the shot glasses in amaretto, then in the graham-cracker crumbs. Fill glasses with hot chocolate and top each with a toasted marshmallow.