Cozy ambient inside, but also with tables on the street, Champagne Socialist is a good place to try natural wines from Europe. You can also go there just to buy a bootle (or more, of course) and drink it at home.
Tiny traditional restaurant with no reservations. Delicious traditional Milanese food, all cooked in their tiny kitchen. Always a queue so arrive early!
Wine bar serving a great selection of wines by the glass and bottle, alongside a selection of small plates. Lovely interior and friendly staff. Booking suggested.