Rinse the rice and soak for 50 minutes. Drain well and put in a rice cooker with the water. When done, transfer to a large bowl and let cool 2 minutes. Add sugar and butter and stir well.
Meanwhile, rinse and soak the dates in warm water 1/2 hour. Cut in halves, removing pits. Finely chop the pumpkin seeds, peanuts and walnuts. Mix the walnuts with the red bean paste.
Oil a shallow 18cm bowl to prevent sticking. Place the pineapple slice in the bottom, and place the pumpkin seeds and peanuts in the very centre.
Place the dates and mandarin segments radially around the pineapple, like a shining sun. Place 1/2 the rice in the bowl and flatten. Spread the red bean paste evenly on top. Fill the bowl with the rest of the rice and flatten.
Place the bowl in a steamer, cover and steam over medium high heat 25 minutes.
Remove from heat and let cool 5 minutes. Run a knife around the rim of the rice. Place a plate over the top, flip over, remove bowl and serve.