Step 1

For the shells: Whisk together the egg, egg whites, and sugar in a medium bowl until pale and fluffy, 3 to 4 minutes. Add the melted butter, heavy cream, vanilla, flour, and salt and whisk until smooth.

Step 2

Prop either end of a wooden spoon between two cans or loaf pans. Preheat a waffle cone maker (at least 6 inches in diameter). Spray both sides of the waffle cone maker and add 1 tablespoon of batter to the center before closing. Cook the waffle until golden brown, about 2 minutes. Gently lift the waffle cone with a small offset spatula and drape over the wooden spoon handle to form a taco shell. Let cool before setting aside on a parchment-lined sheet tray.

Step 3

To assemble: Gently fill the taco shells with ice cream using an ice cream scoop. Place the tray of tacos in the freezer until the ice cream has refrozen, about 45 minutes.

Step 4

Fill the bottom of a medium saucepan with about 1 inch of water and bring to a simmer over medium-high heat. Place the chocolate in heat-proof bowl that is slightly larger than the saucepan and set over the water. (The bowl should sit on top of pan without its bottom touching the water.) Heat the chocolate, stirring occasionally with a dry rubber spatula, until mostly smooth and melted, 3 to 5 minutes. Remove the bowl from the saucepan; continue stirring until completely smooth. Stir in the coconut oil.

Step 5

Dip the round edge of the taco in a rolling motion into the chocolate to coat the ice cream completely. Immediately sprinkle with chopped peanuts. Set on a sheet tray lined with parchment paper and return to the freezer. Once completely frozen, store in an airtight container for up to 1 week.