Prep the tofu: Press the tofu for 10–15 minutes to remove excess moisture.
Cut into 3/4-inch cubes. Toss gently with 2 tbsp cornstarch and a pinch of salt until lightly coated.
Whisk the sauce: In a bowl, whisk soy sauce, rice vinegar, sesame oil, maple syrup, broth, and 1–1.5 tbsp cornstarch. Add chili-garlic sauce if using.
Set aside.
Crisp the tofu: Heat 1–1.5 tbsp oil in a large skillet or wok over medium-high heat. Add tofu in a single layer. Cook 7–9 minutes, turning occasionally, until golden and crisp on most sides.
Transfer to a plate.
Stir-fry the vegetables: Add another 1 tbsp oil to the pan. Add broccoli and carrot; cook 2 minutes, stirring. Add bell pepper, snap peas, and the white parts of the green onions; cook another 2–3 minutes until crisp-tender.
Add aromatics: Push veggies to the sides.
Add garlic and ginger to the center with a splash of oil if needed. Sauté 30 seconds until fragrant.
Combine and sauce: Return tofu to the pan. Whisk the sauce again (cornstarch settles) and pour it in.
Toss everything to coat. Cook 1–2 minutes until the sauce turns glossy and thick and the tofu is heated through.
Finish and serve: Remove from heat. Stir in the green onion tops.
Taste and adjust seasoning—more soy for salt, vinegar for brightness, or syrup for sweetness. Serve over rice or noodles and top with sesame seeds. Add a squeeze of lime if you like.