Walk the streets of Chengdu, the capital of China’s southwestern Sichuan province, at dusk and you’ll encounter a pandemonium of smells. On one corner, an older woman tosses just-fried potatoes with scallions, garlic, salt, and sugar for a line of hungry customers; across the street, a man portions out single servings of cold noodles slicked in black vinegar and a dash of chile oil. In a booth wedged between two clothing shops, a middle-aged couple fries up guokui, a crispy meat-filled pancake topped with fermented vegetables and a sprinkling of Sichuan peppercorn. Down the street a bit, the next generation of street vendors hawks third-wave coffee to young people in cups with splashy logos.