Mash the bananas well.
Mix butter and sugar until creamy.
Add the eggs one at a time, mixing well after each addition.
Add the mashed bananas and vanilla extract, then mix to combine.
Sift flour, baking powder, and salt, then add and mix in.
Pour the batter into a pound cake pan.
Bake in a preheated oven at 180°C for 40–45 minutes.
Let it cool, then slice.