Nestled on the east end of Cortland is Sandbox Bakery. A few doors down is 903, its newer sister restaurant. The owner of both, Mutsumi Takehara, has roots in La Farine, Chez Panisse, and the Slanted Door so you can expect a good mix of skillfully made European and Asian fusiony treats.
The quality of the baked goods is always stellar. The chocolate croissant is a great balance between flakiness and chewiness, and probably my favorite in the city. They score points for having a more consistent product than I've experienced at other SF places. The buns have a nice brown glaze on the top and enough structure to not deflate under the weight of their toppings and fillings. My favorite are the savory curry bun and the sweet banana chocolate heart, a bun that inherits the best qualities of a banana cream pie, a chocolate croissant, and a sundae.
Even though the bready parts are always great, I haven't enjoyed all the toppings/fillings. I don't know what they were thinking with the corn and bechamel I had this morning, and there are a few others that I've thought were interesting ideas that failed to taste pleasant. My experience has been that if it sounds weird, it's probably not that great.
I've only been to 903 once, but if the item I had is representative of what they do, I'm going back very soon. The woman at the counter told me their signature item is the Fried Chicken Rice burger (fried chicken, mixed greens, sriracha, and soy lemon vinaigrette). The bun is made up of a rice patty that's been grilled. It's not as crunchy as a Iranian Tahdig, but the rice holds together well and was a nice departure from the flour based buns at I'd been stuffing my face with at Sandbox. The marinated and fried chicken has a great flavor and crunch, and it so good that I found it difficult not to liberate it from the sandwich and eat it by itself. They currently have a tofu rice burger, and six sandwiches served on a variety of more traditional breads (Crispy shrimp balls; pulled chicken; chicken tsukune burger; smoked brisket; fried oyster; and katsu).
http://sandboxbakerysf.com : 833 cortland avenue
903 doesn't have a webpage yet, but is at: 903 Cortland Ave; Break/Lunch Tues-Sun 9-3; Dinner: Tue-Thurs 5-8, Fri-Sat 509