In a small bowl, whisk together soy sauce, sesame oil, rice vinegar, maple syrup, cornstarch, and water. Set aside.
- Heat neutral oil in a large skillet or wok over medium-high heat.
- Add garlic and ginger. Sauté for 30 seconds until fragrant.
- Add onions and mushrooms. Cook for 5–7 minutes, stirring occasionally, until mushrooms release moisture and begin to brown.
- Add bell peppers, carrots, and broccoli or snow peas (if using). Stir fry for 3–5 minutes until vegetables are crisp-tender.
- Stir the sauce mixture again and pour into the skillet. Toss everything to coat.
- Cook for 1–2 minutes, stirring constantly, until sauce thickens and clings to vegetables.
- Remove from heat and garnish with sesame seeds, green onions, or chili flakes if desired.
- Serve hot over rice, noodles, or grains.