Visiting Portland... where MUST we go??
I don't see a lot of recommendations so far specifically for locally-grown food, so I'll chime in with some places that offer (at least to some extent) local, seasonal food:
Grand Central Bakery
Lovely Hula Hands
Hot Lips Pizza
The chef at Clyde Common is doing his damned best to utilize all he can to serve to his guests from the whole pigs he recieves once a week. Whether it is recognizable cuts for menu items, or the "other bits" for house charcuterie, an admirable effort with a very tasty outcome.
Kenny & Zukes for their pastrami...
Pok Pok for Thai...
Le Pigeon or Sel Gris for high end...
Apizza Scholls or Ken's Artisan Pizza for pizza...
Teardrop Lounge for cocktails...
Toro Bravo for tapas...
The Asian Station food cart for xiao long bao...
Wildwood for Pacific Northwest cuisine...
We ain't starving here in PDX.
Pok Pok is rather amazing, but the staff is a tad pedantic. Sometimes amusing. Now, I'm not familiar with other Italian places in PDX, but have been to Italy about 15 times since 1992...always to "study" food, and I can honestly say that the ONLY restaurant I've ever eaten at in this country that resembles the flavors I've had in Italy is in PDX: Alba Osteria. Their take on la cucina piemontese is astonishingly "authentic" (talk about a misused word) in the authentic sense of this word. I can't say enough good things about it. No concessions to the American palate, it's the real deal, and that's probably way it stays off the radar. by the way, I've lived in Providence RI and can say that nothing there nor in Boston even comes close to what these guys do (please don't tell 'em I said that on The Hill, I value my skin!) NYC might have a place, but have not found it yet.
I'm new to town and can't offer much else. However, I've found Toast to be a great place for a distinctive take on breakfast, using organic and local ingredients, but creatively without being ridiculous or trendy. It's yummy. Oh, since the east coast is still not caught up on it's coffee consciousness, don't miss the Stumptown Coffee experience. Certainly some of the best in the USA...many of the top shops and restaurants use Stumptown beans, so why not get a shot or espresso or a cappuccino properly made...from the local source? Worth the trip....but several locations make it a short one.
Alba Osteria stays off the radar due to their location. If it was in NW, across the river or in downtown, it would be talked about a lot more. I live nearby and have been many, many times and I can honestly say that they have the best pasta and gnocchi anywhere. It's always a great meal there and their wine list is also very good (and reasonable).
Other consistently great places that don't get talked about as much:
Pambiche (for Cuban food and awesome cakes/desserts)
Karam (for Lebanese)
Since your staying Downtown, it means that you have easy access to the Streetcar, which goes all the way into NW 21st/23rd. That's where you'll find places like Carlyle, Wildwood and Paley's Place, among others.
I'm a big fan of Karam, and of Lebanese and Persian food in general.
Park Kitchen is a good suggestion also, in the north park blocks. Nearby are places like Hiroshi Sushi, Ten-01, Teardrop Lounge, Via Delizia and D.F.