What is des pommes de terre in English?

"Creamed potatoes" and "mashed potatoes" are English equivalents of the French phrase pommes de terre mousseline. The feminine prepositional phrase also occurs as mousseline de pommes de terre. The pronunciation will be "puhmd ter moo-sleen" in northerly French and "puhm-muh duh ter-ruh moo-suh-lee-nuh" in southerly French.