Preheat oven to 400 degrees
Line a baking sheet with parchment paper
Mix almond flour, coconut flour, baking powder and salt together in a large mixing bowl
Cut in cold coconut oil with a fork until the mixture is crumbly
Place the bowl in the refrigerator for 10 minutes
In a medium bowl whisk egg whites until they are very frothy
Fold the egg whites into the chilled flour mixture until well combined
Scoop about 1/4 cup of dough onto the baking sheet and smooth the top to form each biscuits, an ice cream scoop works well in this step
Bake for 15-18 minutes, or until the tops are golden brown
Serve warm or store in an airtight container in the refrigerator