Mix the flour, sugar and bicarbonate of soda in a mixing bowl with a pinch of salt. Make a well in the centre and pour in the buttermilk and egg, whisk together until smooth, then set aside for 30 minutes.
For the butterscotch sauce, melt the butter in a small saucepan over a medium heat, then add the sugar and allow to dissolve. Simmer for 4-5 minutes, stirring regularly, until golden. Take off the heat and stir in the cream, vanilla and salt.
Heat a large frying pan over a medium-low heat. Melt a knob of butter, then add a small ladleful of the batter and spread to a circle roughly 12cm in diameter – cook 2-3 at once, if possible. Flip after 2-3 minutes when bubbles appear, then cook for another 2-3 minutes. Repeat to make about 8 pancakes.
Stack onto plates, top with the banana and spoon over the warm butterscotch sauce. Serve with whipped cream too, if you want.