Cream the butter and sugar until fluffy. Beat in the egg, then fold in the flour mixed with the baking powder
Flatten the mixture into the tin using a small angled palette knife and bake for 12-15 minutes or until light golden
Remove from the oven and allow to cool in the tin for 30 minutes
Spread the dessicated coconut evenly on a shallow baking tray and toast in the oven for no more than 5 minutes. Shaking once or twice to get an even colour
For the filling, spread the cooled base with the jam/jelly
Heat a large frying pan over a high heat. Add the sugar to the pan and melt to form a caramel, swirling all the time
Carefully add the rum (I had an unplanned flambé experience!), then whisk in the butter
Add the banana slices and toss gently or turn with tongs until coated & caramelised
Layer on top of the raspberry jam/jelly, then place in the fridge for 30 minutes
For the custard, put the milk in a saucepan, bring to the boil, then reduce the heat
In a bowl, whisk the egg yolks, sugar, custard powder and an extra splash of milk together until smooth
Pour a little of the hot milk on to the mixture, whisk well, then add it back to the hot milk
Cook the custard over a low heat, stirring constantly with the whisk, until the mixture is very thick
Pour the custard on to the banana caramel mixture then sprinkle the toasted coconut on top
Refrigerate for 30-40 minutes until the tart is set