What’s that slurping sound you hear? It’s the joyful noise of ramen freaks lapping up noodles and broth, hoping for a heavenly taste of Japan’s ultimate fast-food comfort. A mini Ramen Craze has seized Portland: At the just-opened Mirakutei on E Burnside Street, lines—and debates over its place in the ramen firmament—have started forming. Meanwhile, Bokebowl, a monthly ramen “pop-up” restaurant launched last fall, has built an army of followers with...