The first place I tried alfajores in S.F. was at Taqueria La Corneta. Today I went to the Alemany Farmer's Market and found that there's a new coffee stand called Cafe del Sur (or something like that) where they have beautiful alfajores. I bought one for $1.25 and it was delicious. It was prettier than La Corneta's version and it was stuffed with dulce de leche.
I am heading to Destino on Market St. on Thursday and will save room for their alfajores, which they also seem to sell at Gump's. Has anyone tried the alfajores at Tango Gelato on Fillmore?
FYI - alfajores South American sandwich-like cookies. Dulce de leche is sandwiched between two butter cookies that are sprinkled with powdered sugar. They are worth a try if you like dulce de leche.