Boil & Drain Ramen: Bring a pot of water to a rolling boil. Drop in the two blocks of ramen noodles (discarding flavor packets) and cook for just 2 minutes until pliable and loosened but still firm. Drain immediately, rinse briefly with cool water to halt cooking, and toss with 1 teaspoon of sesame oil so they do not stick.
Whisk Savory Stir Fry Sauce: In a small bowl or measuring cup, whisk together beef bone broth, low-sodium soy sauce, honey (or brown sugar), rice vinegar, toasted sesame oil, minced garlic, grated ginger, and cornstarch until the cornstarch is completely dissolved.
Sear Beef at High Heat: Heat 1 tablespoon of cooking oil in a large deep cast-iron skillet or wok over medium-high heat until shimmering. Add the thinly sliced beef flank steak in a single layer and sear without moving for 90 seconds until caramelized and browned on one side. Flip and cook for 1 minute more until just browned. Transfer beef to a plate.
Flash-Steam Broccoli: Add the remaining 1 tablespoon of oil to the same hot skillet. Toss in the broccoli florets and white scallion parts. Splash in 2 tablespoons of water, cover immediately with a lid, and steam for 2 minutes until tender-crisp and bright emerald green.
Simmer Sauce: Uncover the skillet, give your prepared stir fry sauce a quick re-whisk, and pour it directly into the skillet with the broccoli. Bring to a rapid simmer for 60 seconds until the sauce turns clear, glossy, and thickens into a rich glaze.
Toss Everything Together: Return the seared beef slices (and any resting juices) along with the cooked ramen noodles into the skillet. Use kitchen tongs to toss vigorously for 1 to 2 minutes over medium heat until every ribbon of noodle and beef strip is evenly coated in sizzling savory glaze.
Garnish & Serve Warm: Remove from heat immediately. Scatter sliced green scallions and toasted sesame seeds generously over the top. Serve immediately in wide bowls with chopsticks!