Line a 9 inch (23 cm) springform cake tin with baking paper and grease the sides with butter.
Measure the flour, cornflour, salt and baking powder into a bowl.
Cream the butter, sugar and vanilla extract together in the bowl of a stand mixer until it is pale and fluffy.
Beat in the eggs, one at a time, alternating with a tablespoon of the dry ingredients.
Gently add the rest of the dry ingredients.
In a separate bowl, mash the bananas with the lemon juice. Add the yoghurt and mix to combine everything together. Add this to the batter and stir through to combine.
Pour the batter into the prepared cake tin. Bake for about 50 minutes, or until a skewer inserted in the middle comes out clean.
Leave the cake in the tin on a wire rack for about 10 minutes before carefully removing the cake and leaving it on the wire rack to cool completely.
To make the frosting, beat together the butter, cream cheese and vanilla extract until it is smooth. Add the icing sugar and beat until you have a thick and smooth consistency. Add 1-2 teaspoons of the lime juice, or to taste. If the frosting is too soft, put it in the fridge for 10 minutes or so until it has firmed up a bit.
Spread the icing over the cake and decorate with chopped pecans.
Frozen bananas work well in this recipe. I like to freeze ripe bananas by breaking them into small pieces and placing them into a ziplock freezer bag. Once defrosted, discard any excess water.
As bananas vary greatly in size, you may need to adjust the baking time depending on how small or large your bananas are.