Preheat your oven to 350 degrees.
Grease a 12-cup muffin pan.
Place the chia seeds and water in a small bowl, and whisk together with a fork. Set aside.
In a large mixing bowl, whisk together the oat flour, coconut sugar, baking soda, and salt.
In a medium bowl, mash the bananas.
To the bowl with the bananas, add the avocado oil, vanilla extract, and chia seed and water mixture. Whisk until it's well combined.
Add the wet ingredients to the dry ingredients and stir them together.
Fold in 1 1/2 cups of blackberries.
Divide the batter between the 12 muffin cups, and sprinkle the rest of the blackberries on top.
Place the muffin pan in the preheated oven and bake for 25 - 30 minutes, or until a toothpick comes out clean with just a few moist crumbs.
Let the muffins cool for 10 minutes in the pan before placing them on a cooling rack to finish cooling.
Enjoy with butter and raw honey!