Kids will love these. To stop your banana slices browning, brush with lemon juice, or use dried bananas if you're baking ahead.
Heat oven to 190C/170C fan/gas 5. Line a bun tin with 8 paper cases. In a large bowl, mix the flour, baking powder and sugar with a pinch of salt.
In a separate bowl, beat the egg, melted butter and milk for 20 secs; add the mashed banana and beat for a further 5 secs until everything is nicely mixed.
Pour the banana mix into the flour and fold everything together. Once it is almost combined, add 85g of the white chocolate – the mixture will still look a little lumpy. Spoon the cake mix into the paper cases and bake for 18-20 mins until golden and risen, and a skewer inserted comes out clean. Cool on a wire rack.
Meanwhile, melt the remaining white chocolate over a pan of barely simmering water. Allow to cool a bit, then spread on top of the cakes. Add a couple of slices of banana and sprinkle with cinnamon.