Bring a pot of water to a boil and cook lo main noodles. Drain rinse very well. Transfer to a mixing bowl. Mix in cabbage and shredded carrots and set aside.
Make the peanut sauce by combining all dressing ingredients in a sauce pan over medium-low heat, slowly whisking in milk to make the dressing richer. Cook, stirring constantly, until the sauce is smooth and well blended, about 3 minutes. Gently mix sauce into noodles and vegetables. Transfer to a serving platter and sprinkle with peanuts and scallion.