Variations of chewy wheat noodles tossed with a savory pork and fermented black bean sauce can be found throughout China and Korea. In the former, it is called zhajiangmian; in the latter, it is jjajangmyeon. Our recipe is a simplified, meat-free spin on the dish and uses widely available prepared Chinese black bean garlic sauce as the flavor base. Look for it in sold in jars in the Asian aisle of the supermarket.