Updated. It's still good, but it's been bumped to 4 stars because avenue open kitchen makes a way better peameal.
It's a big tourist spot, so if you don't like lines, you may want to avoid the weekends. But this place is popular for a reason. It's a stack of delicious peameal bacon on a bun. It's a classic. A lot of people don't know the history of peameal and the significance of this sandwich in Toronto, but it starts right here at St Lawrence Market. Peameal bacon was invented right here in the market in the 1800's when they used to roll the pork loin in cornmeal as a way of preserving the meat (since electric refrigeration didn't exist yet). After rolling the whole pork loin, they used to hang it on hooks by the windows of the market so the cool breeze of the lake would keep the rolled meat cool. (the market used to be on the lakefront before the city was built out further onto the lake)
So peameal was made as a way of preserving the meat originally, but obviously they struck pink gold. The stuff is amazing. So if you're eating a bacon sandwich at carousel, you're eating a truly traditional and historic Toronto dish. This is the taste of our heritage. And this is where it all started.
I love it because it's all about the bacon. It's just a bun with a stack of meat on it. Grab some sweet or spicy mustard on the side if you want. They don't usually tell you that it's there.