Preparation

Make the syrup

• Put the cocoa powder in a small bowl. Combine the sugar, salt, and water in a small saucepan, bring to a low bowl, and boil for 2 minutes. Whisk enough of the hot syrup into the cocoa to form a smooth paste, then whisk in the remaining syrup. Stir in the vanilla. Let cool.

Make the floats

• Pour a tablespoon of cocoa syrup and a tablespoon of coffee liqueur into each of six tall 10- to 12-oz glasses. Add the scoops of ice cream. Add the stout, pouring it gently down the side of each tilted glass to prevent too much head from forming. Top each float with a dollop of whipped cream, and drizzle with a little more cocoa syrup, if desired. Serve immediately, with straws and long-handled spoons.

  

Make Ahead Tips

The syrup can be stored in a squeeze bottle or jar in the refrigerator for up to 3 weeks.