El Porteno, sin duda! The owner is from Buenos Aires and he makes a lovely, flaky crust, just thick enough not to break, Beef is grassfed, chicken(with chorizo) is organic, and there's one with corn (humita) as well. There are ham with cheese, and another flavor, cheese and onion, I believe. $3 apiece.
Empi isells Artentine empanadas at local farmers markets. Here's two reports about them. They also do catering so maybe they make other Argentinean dishes.
There's not a lot of Argentine food in the Bay Area. Here was a similar post from early this year but it focused on restaurants.
There's a vendor at the Alamany Farmers market that sells Chilean empanadas and someone who posted about how these differ from Argentineas said they are pretty similar
Someone mentioned that Lucca in SF had some Argentinean items
Villa Del Sol is an Argentinean restaurant in South SF, so that might be an option.
Sorry for taking so long to reply, but Chowhound is so slow for me I can't get to many things anymore.
1100 Valencia St, San Francisco, CA 94110
Villa Del Sol Argentinian
423 Grand Ave, South San Francisco, CA 94080
501 Lakeville St, Petaluma, Ca 94952
Not sure if it's the same place (Empi's) but I've had some empanadas at different farmer's markets (old oakland or lake marriot) and while they were pretty good -- they charged $5 or $6 bucks for two tiny empanadas...I'm talking sub-dim sized. For that much I expect enough to satisfy.
In Berkeley, you might check with Cafe Valparaiso to see if they can make a bunch to order. Their food isn't the best, but it isn't bad - it is chileno, not argentino. I don't know what kind of alfajores they make (if any) but they might be substantially different from alfajores argentinos. You might want to see if you can find Havanna Alfajores somewhere around here - they are packaged and exported from Argentina (and shelf stable for some time) but they aren't bad.
Thanks for the tip. Funny you mentioned alfajores because I REALLY like those things. Re: packaged one, I had some at food show and they weren't good but I believe they were mass produced. I get my fix from Caffe Centro in South Park. I get the chocolate dipped one...I don't know if that's a bastardization but they're great.