Preheat the oven to 350°F. Line a 12-cup muffin pan with muffin liners.
In a large bowl, whisk together all the wet ingredients: applesauce, coconut oil, coconut sugar, flax egg, and vanilla. Whisk until well incorporated.
Add oat flour, almond meal, baking powder, baking soda and salt. Whisk together until just incorporated, making sure no flour patches remain. Gently fold in blueberries.
Using a large cookie scoop, scoop and drop batter evenly into muffin cups.* Smooth batter into an even layer, with a domed top (rise) in the center. Optional: press blueberries gently into the tops of the muffins.
Bake for 16-22 minutes. Mine took 19 minutes. Insert a toothpick in the center of one muffin to check for doneness. It will come out clean when the muffins are ready. Allow to cool on a cooling rack for about 1 hour. Lift out and enjoy! Storing instructions below.