Beat the egg whites for 1-2 minutes until foamy. Briefly whisk in the heavy cream and vanilla extract. Add the flour and brown sugar. Whisk until just combined. Lightly whisk in the melted butter.
Heat a skillet over medium-low heat and then lightly grease it. Use a #40 dough scoop (about two tablespoons) to scoop batter onto the hot skillet and spread it out in a circle. Sprinkle with cinnamon sugar for the churro version if desired. Flip to cook on the other side. Takes 3-4 minutes.
Remove from the skillet and drape over a foil-covered book spine (or use a wooden spoon handle) to cool and form the taco shape.
Repeat with the remaining batter.
Ice Cream Tacos
Prepare a pan for chilling the ice cream tacos. Make grooves/zig-zags with a piece of foil. Place the foil in the pan and put it in the freezer.
Use a spoon to fill the taco shells with your ice cream of choice. Immediately place them in the prepared pan in the freezer to harden.
Remove an ice cream taco from the freezer, dip the ice cream in the chocolate shell, allow the excess to drip off, immediately sprinkle with your chosen garnish, and return to the prepared pan in the freezer.
Once the ice cream tacos have hardened, transfer them to a freezer bag or airtight container and store them in the freezer for 1-2 months. You can wrap each one individually before storing them, if desired.
Video
Notes
When using a waffle cone maker, add 1/3 cup of all-purpose flour.