Peel & slice 2 of the bananas

Grease the base of an 18cm/7in loose-based, deep cake tin, line the base with the banana slices, overlapping slightly

Put all the butterscotch sauce ingredients into a small saucepan

Stir over a medium heat using a wooden spoon until the mixture is well combined and begins to bubble

Reduce the heat and simmer for a further 5 minutes, stirring occasionally

Pour enough of the sauce into the cake tin to almost cover the bananas

Preheat the oven to 180ºC/350°F/Gas mark 4

In a large mixing bowl, cream the butter with the sugar until fluffy

In a small measuring jug, lightly whisk the eggs

Slowly add the eggs to the sugar & butter mixture, stirring continuously

Add the rum and vanilla essence and mix until combined

Sift the flour and baking powder into a small mixing bowl

Add the flour in 3 batches to the batter, alternating with adding the milk, stirring continuously, until well combined

Chop the last banana into cubes and gently fold into the batter

Pour the mixture carefully & evenly over the butterscotch-covered bananas

Bake for 50-60 minutes until a skewer inserted into the middle comes away clean

Leave to rest for 10 minutes before running a sharp knife around the circumference of the cake tin and carefully flipping it over onto a plate

Lift off the cake tin outer rim, run the knife carefully across the tin bottom before lifting it off

Serve warm with the rest of the (reheated) butterscotch sauce