I invented this recipe using low carb wheat flours long ago and it grew to be a low carb kitchen favorite amongst many people eating that way. But sadly I couldn't eat it any longer after discovering my intolerances. The appeal of this is that you can mix it and bake it in a bowl in the microwave. Its a single serving thing.

So I finally found a substitute I like a lot, using coconut flour.

Banana Nut Bowl Muffin (or cake really)
1.5 Tbl coconut flour
1 egg (Large or better)
1/2 tsp banana extract
1-2 Tbl chopped walnuts
1 tsp baking powder (could probably use less)
1 tsp oil (possibly optional)
1-2 Tbl sugar or substitute for sugar

I put the dry ingredients (except walnuts) into the bowl and mix. Then I crack in the egg, add oil and extract, sweetener if it is liquid and stir vigorously. When it becomes like a thick paste add enough water to make it about the consistency of thin pancake batter. Coconut flour is THIRSTY stuff, is absorbs water like a sponge.

When it is well mixed add in the walnuts. Microwave for about 1.5 minutes until it stops looking wet on top and doesn't bubble. Do not overcook or it'll get dry.

Variations include using Da Vinci or Torani syrups instead of extract/water, using berries instead of walnuts. You can make savory ones using spices and slice it like bread. One can also add flax meal for various effects, but watch that it doesn't get dry.