Cong you mian (葱油面, scallion oil noodles) is one of the simplest and most beloved preparations in Shanghai home cooking — plain noodles dressed with a scallion-infused oil made by very slowly frying large quantities of scallion in oil until they caramelize and crisp into golden-brown shreds, the oil absorbing all their sweetness and fragrance in the process. The resulting scallion oil is deeply aromatic, nutty-sweet, and profoundly savoury. Dressed noodles in this oil, with a splash of dark soy sauce and light soy sauce, constitute one of the most satisfying single-ingredient noodle dishes in any cuisine.
The scallion oil: Use both the green parts and white parts of scallions. Slice 200g of scallions into 4cm lengths. In a cold wok or saucepan, combine the scallions with 150ml neutral oil and 2 tbsp sesame oil. Heat over low-medium heat. The scallions will release moisture and begin to sizzle and bubble. Continue cooking over low heat for 20-30 minutes — the scallions gradually lose their moisture, shrink, and deepen in colour from green to golden-brown to caramel-brown. They should be completely wilted and beginning to crisp. At this point, strain the oil through a fine-mesh sieve. Reserve both the oil and the caramelized scallion shreds. The noodle assembly: Cook thin egg noodles or plain wheat noodles. Drain well. In the serving bowl: 2 tbsp scallion oil, 1 tbsp dark soy sauce, 1 tbsp light soy sauce, a pinch of sugar. Add the drained hot noodles. Toss vigorously. Top with the reserved caramelized scallion shreds.
Fuchsia Dunlop, Land of Fish and Rice (2016); Fuchsia Dunlop, Every Grain of Rice (2012)