October has to be the worst month to open a food cart. The cold and damp has set in, but it's still five months until spring brings hordes of pale, undernourished diners out of hibernation craving egg sandwiches and rice bowls. 

If you're going to open a cart in autumn, soup is the smart way to go. And if you're going to specialize in soup, it should probably be Portland's favorite soup. Which brings us to the just-opened Hapa Ramen, in the pod at Southeast Division Street and 50th Avenue, around the corner from the equally brave new So Cold cocktail cart that embraces the drizzle with a hot cocoa cocktail and a toddy with apple cider and bourbon.

Hapa is not yet a rival for Shigezo, Biwa or Yuzu, but it warmed me right up with a fusion of Japanese and Hawaiian ramen made with frozen noodles ordered from the islands.

My favorite dish was the Shaka bowl ($7.50). In fast-paced Japan, Shaka is served in two parts so diners don't have to wait for their soup's broth to cool before slurping. At Hapa, the noodles come cold topped with a halved soft-boiled egg and green onions. There's also a dip cup—filled with a substance that's not quite broth, not quite sauce—that's thick, goopy and obscenely rich thanks to pork belly and shiitake mushrooms. Each forkful is an uppercut of umami.

I also enjoyed the curry ramen ($7-$8), plump noodles topped with nibbles of crispy fried chicken and curls of shiitake mushroom that sit heavy even before you start spooning up the meaty pork broth. It is, perhaps, overkill. But if you're launching a new cart this time of year, I imagine you play the strongest card you have.

  • Order this: Shaka bowl ($7.50).

EAT: Hapa Ramen, Southeast 50th Avenue and Division Street, 560-0393, hapapdx.com. 11 am-8 pm Wednesday-Monday.