1) Place an oven rack in the lower third of the oven. Preheat the oven to 170°C/ gas mark 3. Butter and flour a mini Bundt tin.
2) Place the pineapple in the bowl of a food processor. Pulse until coarsely chopped.
3) In a 25-cm non-stick pan, combine the chopped pineapple, two tablespoons of pineapple juice, sugar, and butter over medium-high heat. Bring the mixture to a boil, stirring occasionally. Cook until the liquid evaporates and the mixture begins to brown, about 10 to 15 minutes. Spoon the pineapple mixture into the prepared tin.
4) In a large mixing bowl, combine the egg whites, water, vegetable oil, almond essence, cake mix, and 150ml pineapple juice. Using an electric whisk, beat the mixture on medium speed for 2 minutes. Pour the batter over the cooked pineapple.
5) Bake for 28 to 30 minutes until the cakes begin to pull away from the sides of the pan and the tops are golden.
6) Allow the cakes to cool for 15 minutes. Place a piece of baking paper on top of the cakes. Put a baking tray, upside-down, on top of the baking paper. Flip the tins over and allow the cakes to cool completely while still in the tins, about one hour.
7) Unmould the cakes and place on individual serving plates.
Cook's Note: This recipe will also work using tinned pineapple (560g) in 100 percent pineapple juice, drained and juice reserved.