Preheat oven to 350 degrees F.
Make flax eggs by combining 2 Tbsp of ground flaxseeds with 6 Tbsps of water in a small bowl. Mix and let it sit for 5-10 minutes to gel up.
In a large bowl, combine the oat flour, baking powder, baking soda, salt, and cinnamon. Whisk until well combined.
In a blender, add the flax eggs, apple cider vinegar, bananas, avocado, coconut sugar, almond milk, and vanilla extract. Blend until well combined and smooth, about 30 seconds.
Pour wet ingredients from blender into the bowl with the dry ingredients. Use a spatula and mix until just combined. Careful not to overmix. Fold in chia seeds, just stir a couple of times.
Pour batter into a lined or sprayed muffin pan. Bake for 18-23 minutes, or until a toothpick inserted in the center is clean. Cool for 10 minutes in the pan then remove the muffins and place on a cooling rack to cool completely.
Enjoy!
They become more flavorful and moist the next day because the flavors had time to meld together, however, they are still super yummy warm out of the oven. Store in a air-tight container or ziplock bag on the counter for 2 days and in the fridge after that, up to a week. Alternatively, you can freeze the muffins too, they thaw well and taste just as good.