We often get asked what the difference is between caramel and butterscotch. Caramel starts with "burnt" sugar, while for butterscotch brown sugar is melted into the cream and vanilla is added. The flavour is enhanced with sea salt. Some say the 'scotch' comes from the colour of whisky.INGREDIENTS3 eggs, room temperature400g (2 cups) sugar375ml (1 cup) vegetable oil3 ripe bananas, mashed85ml ( cup) buttermilk15ml (1 tbsp) vanilla essence420g cake flour5ml (1 tsp) baking powder5ml (1 tsp) bicarbonate of sodaPinch of salt90g ( cup) mixed walnut and pecan nutsButterscotch icing:200g (1 cup) soft brown sugar190ml ( cup) cream70g butter, unsalted1 vanilla pod, halvedDecoration:100g salted pretzelsHandful fresh raspberriesMETHODGrease and line a 23cm square baking tin. Whisk the eggs, sugar, oil, bananas, buttermilk and vanilla essence together in a large bowl and set aside.In a separate bowl, sift the flour, baking powder, bicarbonate of soda and salt together. Add the dry to the wet mixture and stir in nuts.Pour the batter into the prepared pan and bake in an oven preheated to 180°C for 30 minutes. Cover loosely with foil and bake for a further 20 minutes or until a skewer inserted into the centre of the cake comes out clean. Allow to cool before turning it out onto a wire rack.To make the butterscotch icing, combine the sugar, cream and butter in a large saucepan with high sides.Stir gently over low heat until the sugar has dissolved, then scrape the vanilla seeds into the mixture. Simmer gently (about 15 minutes) until the sauce has thickened. (Optional: sprinkle in a little Maldon sea salt.)Once the cake has cooled completely decorate with butterscotch icing, pretzels and fresh raspberries.Serves 12..