Whisk together ½ cup sugar, cornstarch, cocoa, salt, red pepper, egg, and egg yolk. In a heavy medium saucepan, heat milk over medium-high heat until tiny bubbles form around the edge. Gradually stir half of the hot milk into the egg mixture, whisking constantly.
Next, gradually pour the egg mixture into the remaining hot milk, whisking constantly. Cook over medium heat for 10 minutes, or until thick and bubbly, stirring constantly. Remove from heat, add chocolate chips, and stir until chocolate chips are melted and mixture is smooth.
Adapted from Cooking Light