Preheat oven to 180°C/350°F.
Add the bananas into a medium bowl and mash them into a smooth paste with a fork. Then add the vanilla extract, milk, maple syrup, lemon rind, lemon juice and egg to the bowl.
In a separate, medium bowl, add the chia seeds. Using a fine sieve, sift the wholemeal flour, psyllium husk powder and baking powder into the bowl until only the wheat bran remains. Tip the leftover wheat bran into the bowl and mix well with a whisk.
Pour the dry ingredients into the bowl with the wet ingredients. Gently fold the dry ingredients with a rubber spatula until you can no longer see any flour. Transfer the doughnut mix into a medium snap lock bag. (Note 5)
Grease the doughnut pan (I used a silicon doughnut pan from Kmart) with extra virgin olive oil spray. Cut the corner of the bag and pipe the doughnut mix evenly into the moulds. Lightly coat the back of a metal teaspoon with extra virgin olive oil and smooth the surface of the doughnuts.
Place the doughnut tray into the oven and bake for 15-20 minutes. You can tell they are cooked when an inserted toothpick comes out clean. Once cooked, set the tray aside to cool for 5-10 minutes before removing the doughnuts from the pan.
Add the white chocolate, lemon juice, and extra virgin olive oil to a shallow, microwave-safe bowl. Heat in the microwave for 10 seconds, then stir with a fork. Repeat until the chocolate has completely melted and is smooth.
Place the cake rack over a chopping board or sheet of baking paper. Dip the doughnuts into the glaze, hold them over the bowl until the glaze stops dripping and then return to the cake rack. If the glaze becomes too firm, microwave it for another 5-10 seconds. Once all the doughnuts have been glazed, put them into the fridge (with the chopping board/baking paper underneath) to set the glaze.