Wash hands thoroughly, lathering with soap, and rinsing with running water before starting prep.
Preheat oven to 400℉, and line a muffin tin with silicone liners or coat with non-stick spray.
Place dry ingredients in a large batter bowl and whisk to combine.¾ cup whole wheat pastry flour½ cup unbleached flour½ cup peanut butter powder2 Tablespoons ground flaxseed1 teaspoon baking powder¼ teaspoon salt
Place banana into a medium bowl and mash with a small potato masher or fork. If banana is firm, slice before mashing.1 ripe banana
Add liquid ingredients including egg to the banana, and whisk thoroughly.¾ cup plain Greek yogurt¼ cup milk1 egg¼ cup canola oil2 Tablespoons maple syrup1 teaspoon vanilla
In the center of the dry ingredients, make an indentation with a wooden spoon or spatula. Pour the wet ingredients into it. Mix gently, bringing the dry ingredients up from the bottom of the bowl. Do not beat the batter.Add the chocolate chips (if using) to the batter before all the dry and wet are completely unified. Continue mixing to evenly distribute the chips in the batter. There should not be any dry, floury streaks.¼ cup chocolate chips
Transfer batter to the muffin tin, filling the cups ⅔ to ¾ full. Bake for 13 to 18 minutes, until the tops spring back lightly when touched and a toothpick inserted in the center comes our clean.
Remove from oven and let sit in the pan for about 3 minutes before transferring to wire racks to cool completely. If using silicone liners, remove muffins from liners so they don't steam while cooling.
Notes
The nutrition facts include the chocolate chips. Leaving them out of the batter will save a gram of sugar and fat (each), but they make the muffins extra delicious. Of course, you could use walnuts, craisins, or pecans in their place.