Follow the recipe's instructions until the custard is chilled and ready to churn. Before you churn the custard in your ice cream machine, bake the waffle cones.
Waffle Cones
Combine egg whites, sugar, vanilla, melted butter, and milk in a medium mixing bowl. Whisk until smooth.
Add the salt and flour, whisk again until smooth.
Allow the batter to rest while you heat up your waffle cone iron.
Once the iron is fully preheated, spray it down with non-stick spray
Spoon on two tablespoons of batter. Shut the iron and allow it to cook until the iron indicates the cone is done.
Remove the hot waffle cone and immediately shape. To make a taco shape, you must drape the hot waffle over something evenly so it bends in half. To do this, I made even piles of 5 cookbooks, then placed a wooden spoon on top so that the straight end of the spoon was straddling the books. I could then hang the hot waffles on the spoon stick to set in the taco shape.
Leave the cone to set for a few minutes before removing it. Once it has cooled and hardened, you can transport it to a piece of parchment paper.
After you have baked all 8 cones, allow them to rest for at least 30 minutes before scooping ice cream into them. Letting them rest and dry out will prevent them from getting soft and soggy.
Assembly
While the cones rest, churn your vanilla custard in an ice cream machine.
Once the ice cream is churned, wrap each waffle cone in plastic wrap, leaving a small opening on one side for me to spoon the custard into. This will prevent the soft frozen custard from spilling out the other end while you fill it up.
Spoon the frozen custard into the waffle taco until filled. Close the plastic wrap by folding the open end shut. Place the filled cone into the freezer, propped up so that the opening of the taco is facing the ceiling.
Complete all eight cones. Once they are all in the freezer, allow them to freeze and set for at least 4 hours.
Once the ice cream is set, its time to melt the chocolate. Pour the chocolate chips into a microwave-safe bowl. Heat in the microwave for 30 seconds. Stir vigorously. Return to the microwave for another 30 seconds. Stir again. The chips should melt as you stir and distribute the heat. If needed, heat in the microwave one more time. It shouldn't take longer than 1.5 minutes total to melt the chocolate.
Remove the ice cream tacos from the freezer one at a time. Take the plastic off and carefully spoon chocolate on top until the frozen custard is covered in melted chocolate.
Return the taco back to the freezer, propped up so that the chocolate is not touching anything.
Finish all eight tacos with chocolate. Place each in the freezer right after it is completed.
Once the chocolate is set, they are ready to devour! Any leftover choco tacos should be wrapped in plastic wrap and frozen.