Begin by bringing a large pot of water to a boil. Add the wide rice noodles and cook according to package instructions until they are al dente. Once cooked, drain and set aside.
In the same pot of boiling water, briefly blanch the broccoli florets for about 2 minutes until they are vibrant green and tender-crisp. Drain and set aside with the noodles.
In a wok or large skillet, heat the olive oil over medium-high heat. Add the sliced flank steak and cook for about 3-4 minutes, or until browned. Remove the beef from the skillet and set it aside.
In the same skillet, add the minced garlic and sliced mushrooms. Sauté for 2-3 minutes until the mushrooms have softened and the garlic is fragrant.
Return the beef to the skillet with the mushrooms. Add the blanched broccoli, cooked rice noodles, brown sugar, soy sauce, hoisin sauce, sesame oil, ground ginger, crushed red pepper flakes, and pepper. Toss everything together until well combined and heated through.
In a small bowl, mix the cornstarch with a tablespoon of water to create a slurry. Pour this into the skillet and stir continuously for about 1-2 minutes until the sauce thickens and coats the noodles and vegetables.
Remove from heat and serve your Garlic Beef and Broccoli Noodles immediately, garnished with additional crushed red pepper flakes if desired.
