Prepare Your Tin and Oven: Preheat your oven to 180°C (160°C fan/Gas Mark 4). Grease a 2lb (900g) loaf tin and line it with baking parchment, leaving a little overhang on the long sides to help you lift the cake out later.

Combine Dry Ingredients: In a medium bowl, whisk together the plain flour, bicarbonate of soda, baking powder, cinnamon, and salt. Whisking helps to evenly distribute the raising agents and gets rid of any lumps. Set this aside.

Mix the Wet Ingredients: In a large mixing bowl, add the melted butter, oil, light brown sugar, and caster sugar. Whisk them together until well combined. Add the two room-temperature eggs and the vanilla extract, and whisk again until the mixture is smooth and slightly lighter in colour.

Add Banana and Soured Cream: Add the mashed bananas and the soured cream (or Greek yoghurt) to the wet mixture. Fold everything together with a spatula until it's just combined. Don't worry if it looks a little bit lumpy at this stage.

Combine Wet and Dry: Pour the dry flour mixture into the large bowl with the wet ingredients. Using your spatula, gently fold everything together until you can no longer see any dry streaks of flour. What works best for me is to stop mixing the moment it comes together to avoid developing too much gluten.

Bake the Cake: Pour the batter into your prepared loaf tin and smooth the top with your spatula. Bake on the middle shelf of the preheated oven for 55-65 minutes. To check if it's done, insert a skewer or cocktail stick into the centre of the cake – it should come out clean or with a few moist crumbs attached.

Cool Completely: Let the cake cool in the tin for 15 minutes. Then, use the parchment paper overhangs to carefully lift it out and place it on a wire rack to cool completely before slicing. This step is important, as slicing it while warm can make it crumbly.