Make the sauce: In a small bowl, whisk soy sauce, rice vinegar, sesame oil, honey, cornstarch, and water or broth until smooth.
Set aside.
Heat the pan: Place a large skillet or wok over medium-high heat. Add 1 teaspoon oil and swirl to coat.
Brown the beef: Add ground beef and a pinch of salt. Cook, breaking it up with a spatula, until browned and no longer pink, about 4–6 minutes.
If there’s excess grease, carefully spoon off most of it. Transfer beef to a plate.
Stir-fry the aromatics: Add another teaspoon of oil to the pan. Add minced garlic, ginger, and the white parts of the green onions.
Cook 30–45 seconds until fragrant, stirring constantly so they don’t burn.
Cook the veggies: Add broccoli and carrots first. Stir-fry 2 minutes. Add bell peppers and snap peas.
Stir-fry another 2–3 minutes until crisp-tender. Don’t overcook—some crunch is good.
Combine and sauce: Return the beef to the pan. Whisk the sauce again to recombine, then pour it over everything.
Toss to coat and cook 1–2 minutes until the sauce thickens and glazes the meat and veggies.
Finish and season: Stir in the green onion tops and a pinch of red pepper flakes, if using. Taste and adjust salt, soy sauce, or a splash more vinegar as needed.
Serve: Spoon over warm brown rice, quinoa, or cauliflower rice. Garnish with sesame seeds if you like.