Preheat oven to 350°F (175°C) and lightly grease a 6-inch cast-iron skillet with coconut oil.
In a large mixing bowl, whisk together the almond flour, baking soda, and sea salt until no lumps remain.
Incorporate the maple syrup, melted coconut oil, and vanilla extract into the dry ingredients, stirring until a thick dough forms.
Fold in the dark chocolate chips using a spatula.
Transfer the dough to the prepared skillet and press down firmly to create an even layer reaching the edges.
Bake for 12 to 15 minutes until the perimeter is golden brown and the center is slightly soft to the touch.
Remove from the oven and allow to rest for at least 5 minutes to set before serving directly from the skillet.