Preheat the oven to 160 C / Gas 2/3. Grease a 900g loaf tin and line with baking parchment.
Using a stand mixer or handheld mixer, cream butter and sugar until nice and fluffy. Add eggs one at a time, beating well after each addition until pale and creamy. Add Greek yoghurt and vanilla, and reduce mixing speed.
Add flour and bicarb (mixer on nice and slow by now). Add banana and mix until it is just mixed in. Transfer to the prepared cake tin.
Cook for about 20 to 30 minutes, or until skewer comes out clean. Remove from the oven and allow to cool before slicing and serving.
Consume! Tbh, cakes never last long in my house but I do find banana ones need eaten quicker as they tend to go stodgy.