Cook the ramen noodles according to package directions until just tender. Drain, rinse briefly with cool water, and set aside.

In a small bowl, whisk together the soy sauce, oyster sauce, hoisin sauce, brown sugar, rice vinegar, beef broth, and sesame oil. In another small bowl, mix the cornstarch with 2 tablespoons water to make a slurry.

Heat 1 tablespoon of vegetable oil in a large skillet or wok over medium-high heat. Add the sliced beef in a single layer and cook for 1 to 2 minutes per side until browned. Remove the beef from the pan and set aside.

Add the remaining 1 tablespoon of oil to the same pan. Add the broccoli and stir-fry for 2 to 3 minutes. Add a splash of water if needed, cover for 1 minute, and cook until the broccoli is bright green and crisp-tender.

Stir in the garlic and ginger and cook for 30 seconds until fragrant.

Return the beef to the pan, then pour in the sauce mixture. Bring to a simmer and stir in the cornstarch slurry. Cook for 1 to 2 minutes, stirring, until the sauce thickens.

Add the cooked ramen noodles to the pan and toss everything together until the noodles are evenly coated and heated through.

Top with sliced green onions and sesame seeds if using. Serve immediately.