Q. Is it permitted to spray whipped cream from a spray can on a dessert on Shabes?

A. The main issue with using canned sweetened whipped cream propelled by nitrous oxide, for decorating desserts, ice creams and cakes on Shabbos, is the prohibition of molid or creating something new (Shabbos 51b). Inside the can the cream is in a compressed liquid state, when sprayed it changes temporarily, for counted minutes, to a firmer self-standing foam.

Some Poiskim maintain it should not be used in Shabbos (Hilchos Shabbos Bamitbach p.961 in the name of Horav M. Klein and Horav M. Shtern Zt”l, 39 Melochos 2 p. 371). Some however permit its use. (Rivavos Ephraim O.H. 8; 158: 11, Orchos Shabbos 15: 45, Hemdat Yamim, Balak 5771)

Horav Shlomo Miller’s Shlit”a opinion is that when needed you are allowed to use it on Shabbos.

Rabbi A. Bartfeld as revised by Horav Shlomo Miller Shlit”a