Add 1/2 tablespoon of oil to the pan, and stir fry the onion until translucent over medium high heat, lightly sprinkling with salt and pepper. When the onion is almost done, stir-in the scallion and cook briefly. Transfer to the bowl with the noodles. Stir fry the carrot for 1 to 2 minutes until softened. (Do not overcook. The vegetables should be crisp.) Transfer to the bowl.