Whisk the egg yolks together in a bowl with the maple syrup. Set aside.
Combine the cornstarch, sugar, and salt in a medium saucepan. Add the cream and milk and stir completely. Heat over medium low or low until just coming to a boil. Add the coffee, the chocolate or chocolate chips and peppermint chips and stir over low heat until melted and smooth.
Pour 1/3 of the mixture into the egg yok mixture, stirring with one hand as you pour with the other. Stir completely before adding the mixture back to the saucepan. Continue to cook for 1½-2 minutes more. But do not let the mixture come to a boil.
Remove from the heat. Add the vanilla and peppermint extract if using. Pour through a fine sieve to a clean bowl. Spoon into individual glasses, stemware, or ramekins.
Pipe sweetened whipped cream over and add garnishes like sprinkles, chopped chocolate or Gluten Free Oreo or Joe-Joe's. Chill for for a minimum of 4 hours covered with cellophane before serving.