Preheat the oven to 325°F.

Whisk together eggs and egg yolks in a large bowl; set aside.

Put milk, heavy cream and sugar into a medium saucepan and heat over medium-high heat until mixture reaches 120°F.

Add chocolate chips and continue to cook, stirring constantly, just until chocolate melts; remove pan from heat.

Working very slowly, pour milk mixture into egg mixture while whisking constantly to warm the eggs without cooking them.

Whisk in peppermint extract.

Divide the mixture among eight 6-ounce custard cups or ramekins then transfer them to a 13-x9-inch baking dish.

Carefully fill the pan with enough water to come about three-quarters of the way up the sides of the cups.

Cover pan with foil and bake until custard is almost firm, 35 to 40 minutes.

Remove cups from the pan and set aside to let cool to room temperature, then cover and refrigerate until chilled through.

To make the sweetened whipped cream, beat the heavy cream in a large bowl with an electric mixer until soft peaks form.

Add sugar and vanilla and beat again until desired consistency.

Serve pots de crème topped with sweetened whipped cream.