May one make oatmeal on Shabbos? It is easy to take care of the bishul problem by using a kli shlishi (according to Igros Moshe OC vol. 4 74:15 and others who hold that there is never bishul in a kli shlishi), but does mixing the oatmeal with water constitute Losh (kneading)?
In terms of Losh - Rabbi Kagonoff writes:
WHAT IS LOSH?
The concept of losh is to combine fine powders or similar small items into a unit by adding liquid (Shevisas HaShabas). Thus, mixing clay for pottery, or cement and sand into concrete, violate the Torah prohibition of losh (see Rambam, Hilchos Shabbos 8:16; Rashi, Shabbos 74b). Similarly, mixing oatmeal or reconstituting instant mashed potatoes violates the Torah prohibition of losh (in addition to whatever prohibitions of cooking may be involved).