Café Souvenir on Bernard Ouest is a great bet for gluten-free brunch in Montreal. They have several gluten-free brunch options, including toast. They also have several build your own breakfast options. I ordered 2 eggs with gluten-free toast, gluten-free potatoes (their roasted potatoes are always gluten-free) and bacon. My date also had a gluten-free plate including a delicious omelette with green onion, chèvre and bacon with a big bowl of café au lait.
This spot was definitely worth the detour as they are more aware of celiac disease than many other brunch places in Montreal.
Their brunch menu can be found here:
1261 Avenue Bernard, Montréal, Québec H2V 3M8
Accommodates gluten-free: Yes
Gluten-free menu: No