Pan Grill Japanese Sandwiches Embarcadero Rob Lam | Tasting Table San Francisco

Pop-up restaurants are sort of like one-night stands: a place to get your greasy groove on with no obligation to return.

Sometimes, though, it's too good to say goodbye.

Pan Grill Sandwich Shop, located on the side of Butterfly Restaurant, was supposed to shutter on November 10, but customer demand has been strong enough that Rob Lam and Eric Young decided to stick around. "There's so much more we want to introduce customers to in the coming weeks," Lam, Butterfly's chef, says.

The "pan" in the name refers to the Japanese milk buns that sandwiches like pork katsu and hanger steak are built upon. Made by Lam and his cooks, the buns are lightly sweet and fluffy, with the faint aroma of buttered bread.

The kimchi pulled pork pan ($7) is saturated with sweet, soy-based "chashu BBQ" sauce–messy in the best way. A curry potato croquette sandwich ($7) with yuzu slaw and mizuna sounds like starch overload, but the crisp vegetarian patty is fiercely flavorful.

Even though it's now permanent, Pan Grill doesn't provide seats, so you have to scout out a hideaway on Levi's Plaza to eat.

Consider it part of the afternoon delight.