Marinate the beef: Mix 1 teaspoon vegetable oil, a pinch of pepper, 2 teaspoons soy sauce, 1 teaspoon oyster sauce, a dash of sesame oil, and 1 teaspoon potato starch. Combine well and refrigerate.

Mix the stir-fry sauce ingredients until well combined.

Heat a pan and sauté garlic until fragrant. Add the beef and stir-fry just until it starts to brown, then transfer to a plate. In the same pan, sauté more garlic until fragrant, then add onion, carrot, and half of the stir-fry sauce. Stir well. Add the macaroni and the remaining sauce. Return the beef to the pan, stir quickly, then turn off the heat. Sprinkle with scallions and cilantro. Serve with soy sauce, chili sauce, or as desired.