In a small mixing bowl, combine your mashed banana and coconut flour and mix very well. Add your nut butter of choice and mix into it- It should be a VERY thick batter.
Using a tablespoon at a time, add milk of choice until you reach a thick batter. Stir through the chocolate chips is desired.
Microwave for 1 minute, or until cooked through.
Preheat the oven to 180C/350F and coat an oven safe ramekin with oil and set aside.
Prepare the mug cake batter, before transferring it into the oven safe ramekin. Bake for 10 minutes.
* Depending on the flour you use and the consistency you want, adjust accordingly.TO STORE: If you'd like to enjoy the mug cake at a later time, you can let it cool completely, before covering and refrigerating it, for up to 3 days. TO FREEZE: Freeze the mug cake by placing it in a ziplock bag and store in the freezer for up to 2 months. Thaw overnight in the refrigerator.