In serving mashed potatos/ sweet potatoes, are these a problem?
1. To adjust the “bumps” on top with a spoon to make it look nicer
2. To scoop out several balls and put them in the bowl to retain the shapes
According to the Rema (end if O:CH Siman 321) it is preferable not to smoothen out food such a mashed potatoes for aesthetic purposes on Shabbos.
Using a scooper is not included in this because it isn’t considered making the potatoes smooth, rather a way of dispensing it, which happens to come out smooth. Therefore it is permitted to use the scooper on shabbos. It is not an issue of making it into a shape, because it is simple shape considered boneh.
Zachor Vshamor – Memareyach, Poskim