1Whisk together soy sauce, rice vinegar, honey, cornstarch, water, sesame oil, and red pepper flakes in a small bowl. Set the sauce aside.
2Heat 1 tablespoon of vegetable oil in a wok or large skillet over medium-high heat. Working in two batches, sear the beef for 2-3 minutes per side until browned but still pink inside. Don't overcrowd the pan. Set the beef aside on a plate.
3Add the remaining oil to the pan. Add garlic and ginger, stirring constantly for about 30 seconds until fragrant.
4Add broccoli florets and toss to coat. Stir-fry for 4-5 minutes, stirring often, until the broccoli is crisp-tender and starting to brown in spots.
5Pour in the sauce and return the beef to the pan. Toss everything together for another 2-3 minutes, stirring constantly, until the sauce thickens and coats the beef and broccoli.
6Taste and adjust with salt and white pepper as needed. Serve immediately over steamed rice or noodles.