According to Barsalou, "the three basic items are fries, cheese, and gravy. Of course, the classic would be with curd cheese, but is it the law? No way! You can do whatever you want as long as it is delicious." Poutine aficionados may disagree; many argue that the "squeaky" cheese is a necessity, but Barsalou is more lenient on the rules.
According to Dustin Gillman, who runs @FoodGuyMTL, the cheese is what makes all the difference. He explains that the potatoes and gravy are “pretty standard, and variations of each are generally OK, but the cheese can make all the difference between a good one and a wrong one.”
So what would those be? “Stay away from mozzarella, brie, or any other really melty cheese," Gillman says. "The curd is the one and only cheese for poutine.”