At the first floor in the Grand Tree, there are two food shops. One near the bar (to the east) where you can make gnome drinks and one near the "restaurant" (to the west) where you can make gnome foods. There is also a bank near the restaurant. I think each shop has 5 pots of butter in stock (maybe more, I don't remember). So by switching worlds and buying and banking everything you can make yourself a nice stock of butter. they dont have butter they have cream there...