To make the Scallion Oil:

Cup of Yum
1. Chop the scallions into 2-inch-long (5 centimeter) pieces and separate the white and green parts. If the bottoms of the white parts are thick (1/2 inch, or 1 centimeter, in diameter or thicker), slice the pieces in half lengthwise.
2. Pat them dry thoroughly with paper towels.
3. In a medium saucepan or skillet, heat the peanut oil over medium heat until warm.
4. Add the white parts of the scallions. Cook, stirring occasionally, until the scallions turn golden, 6 to 8 minutes. If the oil starts to splatter, reduce the heat to medium-low or low heat, or remove the pan from the stove to let the oil cool a bit.
5. Add the green parts of the scallions to the pan and cook over medium-low heat, stirring occasionally, until they turn golden brown and crispy, 10 to 12 minutes. Do not let the scallions burn.
6. Remove the pan from the heat and use a pair of tongs or chopsticks to transfer the scallions to a large plate to cool.

Meanwhile, make the sauce:

1. In a small bowl, combine the light and dark soy sauces and the sugar and stir to mix well.
2. Carefully add the sauce to the scallion oil in the pan and bring to a simmer over medium heat.
3. Reduce the heat to medium-low and cook and stir for another minute or so, until it thickens a bit. Transfer to a medium bowl.

To make the noodles:

1. Boil the noodles (follow the package instructions if not using handmade noodles).
2. Strain in a colander and briefly rinse under cold water to stop cooking. Transfer the noodles to individual serving bowls.
3. Top each bowl with a spoonful of the scallion oil sauce and garnish with fried scallions and sesame seeds (if using). Serve the remaining sauce on the side. 
4. Mix the noodles with the sauce before eating, adding more sauce if needed.