Into each jar, layer 1/4 cup sugar, 1/2 cup cocoa powder, 1 teaspoon cinnamon, and 1/4 cup of marshmallows. Repeat with remaining jars and ingredients. Screw on the lids and affix a label with the recipe below:
To serve: Remove the marshmallows to a plate and mix together the remaining ingredients in the jar. Bring 1 cup of milk to a simmer over low heat. Add 3 tablespoons of hot cocoa mix and stir until completely combined. Pour into cups or mugs and top with marshmallows before serving.