The oldest restaurant located in the main square - Hawełka - has opened a new place last winter in the renovated Czeczotka palace on the corner of Wislna and Sw. Anny (also basically in the main square).
It is (obviously) a very touristy place, and the prices are somewhat higher than elsewhere, but the place is very nice, cosy and relaxing; the constant draft must be really great in the hot summer days, but lst Sunday, when we visited it, it was like +18 outside, and we felt a bit cold there.
The service was okayish, I ordered 'breakfast Czeczotka' (30zl). I liked their black pudding, and the breakfast was quite tasty, though probably not really worth its money, especially considering the (included in the breakfast) cold tastless liquid they called coffee
Overall, there are much better places for a breakfast around, but this one should be great to chill out with a cocktail in the summer - great location, a view on the Main Market square, cozy chairs, and not too crouded with the tourists - I'll be certainly visiting them again.
Restauracja Hawełka
Pałac Czeczotka
Św. Anny 2 / Wiślna 1
11:00-22:00