The Bolhão BB Gourmet (there are six of these around the city) is a great choice any time of the day. At the start of the day you can go there for breakfast and bring a take-away meal for lunch. You can have a hot bun (baked in the premises) in the afternoon and then return for a dinner of, let's say, veal with risotto alla parmigiana. You can come in on weekends too: they have brunch from 12pm to 4pm.
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