A few other notable small food stops in Chicago that I’d recommend based on this past weekend:
Heritage Coffee and Bicycle Shop-- just a great atmosphere, good people, excellent espresso shots and sour cherry lemonade, some bike accessories to browse (and a full repair shop). 
Do-Rite Donuts -- the meyer lemon / pistachio cake donut was delicious, and perfectly cooked (moist fully-cooked cake center, slightly crispy outside). There were also many people in line for their next batch of gluten-free donuts. 
Avec, one of the highlights of the Chicago food trip a few years ago, also does an excellent brunch and we didn’t even have to wait when arriving at 10AM on a Sunday. And their long wooden box-like space is especially pleasant when there’s natural light. Their take on a greens/egg/tuna salad (vaguely Niçoise but with more dressing) was excellent, as was a tomato and baked egg dish (especially combined with the chorizo-stuffed dates).
