Add eggs and sugar to a large mixing bowl, and use a mixer to blend for 90 seconds, until volume doubles in size and mixture lightens.
Add yogurt and vanilla extract, and blend.
Using a wooden spoon, stir in bananas and orange zest.
Whisk together almond flour, baking soda, baking power, and salt in a smaller bowl, then stir into large bowl with the liquid ingredients.
Stir in chocolate chips (if using).
Scoop batter into the lined muffin tin, filling each cupcake liner close to the top.
Bake for 15-18 minutes, or until a toothpick inserted into the middle of a muffin comes up almost clean. Muffins will be lightly browned.
Let cool in muffin tin on rack for 10 minutes, then remove muffins from tin and continue to cool on rack.
Notes
NOTE: If you have leftover muffins, leave them out on a plate at room temperature rather than sealing in an airtight container. If you seal them up, the tops will be sticky the next day. Don't worry, they are plenty moist so will not be stale the next day. If you want to keep them for longer, freeze them in a ziploc freezer bag, then defrost at room temperture when ready to eat. Don’t be afraid to really fill the muffin tin cups. I know most cupcake and muffin recipes will tell you to fill just ⅔ of the way up, but almond flour muffins don’t rise very high so you can add more batter to each cup. I love to use an ice cream scoop for filling muffin cups. Almost a full scoop is the perfect size to fill these cups! Almond Flour Tips: If you are planning to store almond flour for over a few weeks, you should keep it in the refrigerator or freezer. Almond flour (and other nut flours) can turn rancid more quickly than traditional flour. You can make your own almond flour with the help of a food processor. Just take a quantity of blanched almonds (you can often find these as blanched, slivered almonds in the grocery store) and blitz in a food processor until they are finely ground.