Start by mixing the soy sauce, sugar, minced garlic, grated ginger, sesame oil, and a sprinkle of sesame seeds in a bowl. Toss the sliced beef in the mixture until fully coated. Refrigerate the beef for at least 30 minutes to soak up all that rich flavor.
Cook the udon noodles as per the package instructions. Once they’re al dente, drain them and set them aside.
Heat some vegetable oil in a wok over high heat. Add your broccoli, bell peppers, snow peas, and julienned carrot. Stir fry for about three to four minutes, just until the veggies are crisp-tender. Set them aside on a plate for later.
Using the same wok, add a bit more oil and toss in the marinated beef. Cook it on high heat for about three minutes until juicy, browned, and slightly caramelized.
Toss the cooked noodles, stir-fried vegetables, and beef together. Stir well, ensuring everything is evenly mixed and heated. Garnish with green onions and more sesame seeds. Serve while hot and enjoy!