With a food reputation based upon the many chains and repetitive Chinese restaurants, there isn't much web information about where is recommended in Cambridge.
Urban Larder is a little off-track, moving away from town when walking from the train station. It is known for bakery good, deli items and reputedly soup served in bread bowls.
A morning brunch of pea soup was a little disappointing. It was a decent soup served with slices of sourdough topped with butter. What didn't impress me was the soup was taken out of a plastic container in the fridge, microwaved and served in a plastic (not a bread) bowl and the sourdough slices lacked the acidic tang.
What was much better were the delicious pasteis de nata (Portegeuse egg custard tarts) they sell from Norfolk Street Bakery and the bread loaves from Loaf For Life which included a delicious Russian Seeded Rye sourdough with sunflower & pumpkin seeds. I'd return to Urban Larder for the bakery items but not the soup. However a better idea might be to head to the actual Norfolk Street Bakery and the next-door deli, for the tarts, bread and sandwich lunches.
The other brunch option in town mentioned is Massaro's (for coffee and sandwiches).