Prep 3 (21cm x 11cm) loaf tins by greasing them with butter and lining with baking paper.
Heat your oven to 160˚ C or 320˚ F.
Place the bananas in a flat bottomed dish, and mash them until there aren't any big bit left. Their mashed weight should be roughly 670g. Set them aside.
Place the butter in a mixing bowl and beat until smooth.
Add the the sugar, and continue to beat until creamed.
Add the eggs and slowly beat them into the creamed butter and sugar until they’ve combined. You can scrape down the sides of the mixing bowl if the butter has accumulated there, and give it a quick beat again.
Add the *double thick plain yogurt and the mashed bananas, and beat until incorporated. *You can substitute the yogurt with water (if you prefer), and increase the butter by 30g to compensate for the change.
Sift in the dry ingredients, starting with the flour, and the salt, and give a slow beat to combine.
Lastly, add the baking soda and baking powder, and give a last slow beat.
Transfer the batter equally into the loaf tins, roughly 570g each.