Butter a non-stick pan (non detachable walls, non springform), mine is 23 cm / 9 inches in diameter.
Sprinkle over the light brown sugar, then arrange the pineapple slices and cherries over.
Add the butter, flour, granulated sugar, eggs, baking powder and bicarbonate of soda to a blender and pulse well to get a smooth paste.
Alternatively, add all ingredients to a large bowl, and use a hand mixer to beat everything together.
Add the pineapple juice to the batter, and mix well again.
Pour the batter over the fruit, and bake in the preheated oven at 180 degrees Celsius (350 Fahrenheit) for 30 minutes, or until a skewer inserted in the middle of the cake comes out clean.
I transferred the cake from the top rack to the middle rack in the oven after 20 minutes to prevent the bake from browning too fast, and I continued to bake it for a further 10 minutes.
Remove the cake from the oven, and leave it to cool down for 3-4 minutes, then run a sharp knife around the edges of the tin to loosen it up.
Place a large plate on top of the tin, and turn the cake upside down swiftly.