Step 1

In a large pot, boil 2 quarts water. Add the baking soda and lo mein. Cook, stirring, until tender. Drain in a colander and rinse under cold water, tossing well, until fully cooled, then drain again. Drizzle with 1 tablespoon of the oil and toss to coat; set aside.

Step 2

In a small bowl, stir together 3 tablespoons water, the soy sauce, sugar, sambal oelek, and ¼ teaspoon each salt and white pepper; set aside. In a 12- to 14-inch wok or 12-inch skillet over medium-high, heat 1 tablespoon of the remaining oil until barely smoking. Add the onion and cook, stirring occasionally, until deeply browned, 7 to 10 minutes; transfer to a plate.

Step 3

Return the pan to medium-high and heat another 1 tablespoon oil until barely smoking. Add the sweet potato and half of the cabbage; cook, stirring, until deeply browned in spots and the potato is tender when pierced with a knife, 3 to 5 minutes. Add half of the peanuts and the garlic; cook, stirring, until fragrant, 20 to 30 seconds, then scrape the mixture onto the plate with the onion.

Step 4

Return the pan to medium-high, add another 1 tablespoon oil and the noodles; increase to high and cook, stirring and tossing, until charred in spots, 3 to 5 minutes. Push the noodles to one side; add the remaining 1 tablespoon oil to the clearing, followed by the beaten eggs (they will immediately puff up). Cook, stirring, until barely set and shiny, 20 to 30 seconds. Stir to incorporate the noodles and eggs, tossing to loosen the strands and break up the eggs, then return the onion and sweet potato to the pan. Add the soy mixture and cook, stirring and tossing, until the noodles have absorbed the sauce and are tender, about 2 minutes.

Step 5

Off heat, stir in half of the remaining cabbage and half of the chili. Taste and season with salt and white pepper. Transfer to a serving dish and top with the remaining cabbage, chili and peanuts. Serve with lime wedges.