Preheat the oven at 185 degrees.
Prepare teh muffin tray with liners.
In a small bowl, mix the flax seed powder with a tbap of warm water. Set it aside to swell.
Into a mixing bowl add the banana and mash it well.
Add the oil, maple syrup, flax eggs and whisk well into a smooth mix.
Add the oat flour, baking powder and baking soda and mix into the wet batter well.
Spoon the batter into the muffin liners till almost the top of each muffin tin.
In a seperate bowl, mix the crumble topping.
Sprinkle a spoonful of the crumble topping on each muffin.
Place the tray in the oven at the higher heat.
Give it 5 minutes and the dome shaped muffin rise will be seen.
Bring down the oven temp to 180 degrees and bake further for 12 to 15 minutes.
The muffins will be cooked and best tested with a skewer that come out clean.
Remove the muffin tray and cool the muffins.
Store in an airtight container in the refrigerator.