Poutine is a feminine noun. Thus we say "une poutine" or "la poutine".
Ma'ame Bolduc, on deLorimier street in Montréal, makes many kinds of poutine with various ingredients, the deadliest of which is arguably "La galvaude", with minced meat and mushrooms added to the usual cheese and gravy.
The gravy should of course be poured after the cheese in order to make it melt appropriately.
The cheese used to make poutine is sold throughout Québec in convenience stores, called "dépanneur", where it is not refrigerated but kept at room temperature to give it a characteristic squeakiness.
Any attempt to tell a Québecois where the best poutine can be found will immediately spark an intense and inextricable debate.