Place milk and half-and-half in a saucepan and heat to a simmer over medium heat.
Meanwhile, stir together the cocoa powder, sugar, and cinnamon. A few teaspoons at a time, stir the hot milk into the cocoa mixture to make a smooth paste. Scrape the cocoa mixture into the saucepan with the milk and simmer 2 minutes; do not let it boil. Stir in the vanilla and keep warm in a thermos.
Pour into small serving cups and place 4 mini-marshmallows on each serving or spritz them with whipped cream. Serve immediately.
Make the marshmallows: Combine the water, the corn syrup, and the sugar in a saucepan fitted with a candy thermometer. Bring to a boil and boil to "soft-ball" stage, or about 235 degrees F.
Meanwhile, whip the egg whites until soft peaks form. Sprinkle the gelatin over the 2 tablespoons water and let sponge.
When the syrup reaches 235 degrees F, remove it from the heat, add the gelatin, and mix. Pour the syrup into the whipped egg whites. Add the vanilla and continue whipping until stiff.
Cover a sheet pan with parchment paper then sprinkle it with powdered sugar. Pour the marshmallow onto the pan and spread it out. Let cool about 2 hours then with a pair of scissors dipped in cornstarch, cut out football shapes.