Preheat oven to 180C/350F. Line a 12-cup muffin pan with muffin cases.
Start by making a flax egg: In a small bowl mix the ground flaxseed with 3 tablespoons water. Set aside for 10 minutes to absorb.
In a large bowl, mix together the spelt flour, oats, sugar, cinnamon, baking powder, bicarb and salt.
In a medium bowl, mash the bananas using a fork. Add the flax egg, almond milk, oil, almond butter and vanilla and whisk to combine.
Add the wet ingredients to the dry and stir gently until just combined.
Toss the blueberries in a little flour and add them to the batter (try not to add too much excess flour). Stir to combine.
Divide the batter between the 12 muffin cases. Top with extra blueberries and a sprinkling of rolled oats if desired.
Bake for about 25 minutes until golden and a skewer inserted into the centre comes out clean. Leave to cool in the pan for 5 minutes before transferring to a cooling rack to cool completely.