Combine all the ingredients in a food processor and process till the dough has the soft texture of your earlobe. (Adjust the amount of whole wheat flour as needed depending on the size of the banana.)
Roll out the dough to fit on your baking tray to a thickness of about 1 mm. Using a pizza cutter, or a similar utensil, cut them into desired shapes.
Poke holes into the dough with a fork. Bake in a preheated oven at 180℃ for about 20 minutes. Allow them to cool on the baking tray.
Story Behind this Recipe
I wanted to easily make some simple cookies that use whole wheat flour and are macrobiotic.
I recommend using super fine whole wheat flour, as introduced in my blog. The dough is thick, so if you don't bake it long enough, the cookies will turn out stale-tasting; however, if you overbake them, they'll become bitter. Every oven is different, so keep an eye on them while baking.