•¼ cup sugar
•1 tablespoon unsweetened cocoa powder
•1 tablespoon cornstarch
•2 cups milk

•2 ounces dark or semisweet chocolate (about 60 percent cocoa solids), finely chopped
•1 teaspoon vanilla extract
•¼ teaspoon kosher salt

Whisk together the sugar, cocoa powder, and cornstarch in a  medium saucepan. Gradually whisk in the milk until the mixture is smooth.

Set the saucepan over medium heat. Cook, whisking constantly, until
the mixture is gently bubbling and thickens slightly, about 3 minutes.
Reduce the heat to low; continue to cook, stirring, for 1 minute. Remove from the heat.

Add the chopped chocolate and stir until it has melted, then stir in the vanilla extract and the salt until well incorporated.

Distribute the mixture evenly among your popsicle molds or small paper cups and place in the freezer. If using paper cups, place a popsicle stick in the center when the mixture is frozen enough for the stick to stand up straight, about 1 hour. Allow to freeze completely, about 6 hours.