I've been playing with this off and on trying to get it right and I think I'm there! I'll have exact measurements soon, I forgot to measure the water this time.
Key points to remember: Don't overcook it! 1.5 minutes is plenty, maybe even a little less. I think the time to stop cooking it is when the bubbles stop forming and it stops looking wet on top. I can see inside my microwave so I just watch it.
My new Bowl Cake tastes like a very light banana/nut muffin.
1.5 Tbl of Coconut Flour (http://www.amazon.com/Simply-Coconut-Organic-Flour-Bag/dp/B000KXLSCQ)
1 tsp Baking powder (less might be possible)
1/2 tsp (approx) of banana extract
1-2Tbl of sugar equivalent sweetener
Ack! I misread my bottle of sweetener.
1 tsp of oil (might be optional)
1-2 T. of chopped walnuts (optional)
I mix the dry ingredients together, crack in the egg, add the other wet stuff and mix until it gets to the consistency of library paste. Then add water until it gets loose and easy to stir (2 Tbl). The coconut flour is THIRSTY and absorbs a lot of liquid. The consistency should be about like thin pancake batter.
Microwave for about 1.5 minutes (in my oven), maybe less. If you overcook it it'll be too dry.
Now it would certainly be possible to substitute the extract and water with Da Vinci syrups, but so far the banana walnut is my favorite. :)
Change: I misread my bottle of sweetener! It was only about 1 Tbl I used, could have been a tad more.