Boil the rice with the sugar and chopped butter lumps. Brush a pudding form with the butter and spread a 3/4″ (2 cm) layer of rice in it. Cover it with a layer of any fruits that are in season and nuts, pressing them well.
Continue to stack a layer of rice, a layer of fruits, etc., ending with fruits, press on them well. Sprinkle with a little sugar.
Put the cake to bake in a water bath for 30 minutes. Optionally, you can invert it once cool.