If a future gastro-historian were to posit the moment that the Los Angeles pop-up thing perhaps reached its apex, she might well finger the appearance of Burger Haven, a lunchtime-only adjunct of Pasadena's Haven Gastropub that has not only popped up within the restaurant itself but also draws much of its menu from the menu that the restaurant already has.
So, if you are hungry for, say, a Haven Burger -- and you might as well be; it is monstrous, juicy and garnished with fistfuls of arugula -- you can walk through the front door and have it on proper stoneware, with fries, for $14, or you can walk in through the pop-up's side entrance off McCormick Alley, have the same burger in a cardboard boat, and pay a couple of bucks less, although the fries will be another couple of bucks on the side.
There are a few burgers at Burger Haven unavailable on the regular Haven menu, including a hiccup-inducing cornflake-breaded chicken model with mashed potatoes and collards where you might expect the mustard and ketchup. Another burger is sluiced with various incarnations of habanero, jalapeño, ghost pepper and smoked serrano that could melt your fillings if you don't treat it with respect. Still, if you've ever been to Haven, you'll know what to expect, right down to the recommendation of a numbingly bitter, artisanal saison with the hellfire burger.