Chocolate Egg Cream

Place cocoa in a small saucepan. Whisk in 1/3 cup hot water, then add corn syrup and sugar. Bring mixture to a boil over high heat. Remove chocolate syrup from heat and cool to room temperature.

Divide 1/3 cup chocolate syrup between two serving glasses and mix in 1/2 cup milk in each. Top with seltzer, stir once, and serve immediately.