Cook the Udon Noodles: Bring a large pot of salted water to a boil. Add the udon noodles and cook according to the package instructions until tender. Once cooked, drain the noodles and set them aside.
Prepare the Teriyaki Sauce: In a small bowl, whisk together the soy sauce, honey, sesame oil, and rice vinegar until well combined. This delicious mixture will serve as your teriyaki sauce.
Stir-fry the Beef: Heat 1 tablespoon of vegetable oil in a large skillet or wok over medium-high heat. Once hot, add the sliced beef sirloin. Stir-fry for about 3-4 minutes, or until the beef is browned and fully cooked. Once done, transfer the beef to a plate and set aside.
Sauté the Vegetables: In the same skillet, add the remaining tablespoon of vegetable oil. Add the minced garlic and ginger, stirring briefly until fragrant (about 30 seconds). Next, toss in the sliced bell pepper and broccoli florets. Stir-fry for about 4-5 minutes, or until the vegetables are bright and tender-crisp.
Combine Ingredients: Return the cooked beef to the skillet with the sautéed vegetables. Add the drained udon noodles, pouring the prepared teriyaki sauce over all the ingredients. Toss everything together gently until well-coated and combined. Continue stir-frying for an additional 2-3 minutes to heat through and meld the flavors.
Serve: Remove the skillet from heat. Plate the noodles in bowls and generously sprinkle with sliced green onions and sesame seeds for a beautiful finish.
Notes
Serve in deep bowls to catch the sauce. Garnish with sesame seeds and green onions for added color.