a layer cake where one of the layers is water. you make the layers of cake on earth and then add a layer that's ice, right. like cake, cream, cake, ice, cake. seal that shit up, keep it frozen.
then you send it to the ISS
then the spacetronauts take the frozen layer cake and microwave it for a few seconds, in zero g
you then have layer cake where one of the layers is water.
water cake

