Banana Sour Cream Cake

Who can resist a tantalising slice of moist banana cake? The secret to a tasty banana cake is a well-aged over-ripe banana. I take my banana fermentation quite seriously, allowing the bananas to ripen on the counter for at least two weeks, letting it go until the skin's about to start growing mould - seriously! I then carefully peel the bananas, plop them into a container, give them a quick mash