Cook or Reheat the Rice: If making fresh, cook rice according to package directions. Fluff with a fork, season with a pinch of salt and a drizzle of sesame oil, and set aside.
Day-old rice works great—reheat gently if needed.
Make the Teriyaki Sauce: In a small pot, whisk soy sauce, water, maple syrup, rice vinegar, mirin, ginger, garlic, sesame oil, and red pepper flakes. Bring to a gentle simmer. Whisk in the cornstarch slurry and simmer 1–2 minutes until glossy and slightly thickened.
If too thick, splash in water.
Prep the Veggies: Slice everything so it cooks quickly. Aim for similar sizes for even heat. Keep harder veggies (carrots, broccoli) separate from quicker-cooking ones (peppers, peas, mushrooms).
Optional Protein: If using tofu or tempeh, sear in a little oil until browned; set aside.
If using animal protein, cook it through in the same pan and set aside.
Stir-Fry the Veggies: Heat a large skillet or wok over medium-high. Add oil. Stir-fry onions and carrots for 2 minutes.
Add broccoli and mushrooms; cook 2–3 minutes. Add bell pepper and snap peas; cook 1–2 minutes more. You want bright color and crisp-tender texture.
Coat With Sauce: Lower the heat to medium.
Return any cooked protein to the pan. Pour in enough teriyaki sauce to coat everything generously, tossing to combine. Warm through for 1–2 minutes.
Assemble the Bowls: Spoon rice into bowls.
Top with the teriyaki veggies (and protein, if using). Drizzle on extra sauce if you like.
Finish and Serve: Sprinkle with sesame seeds and scallions. Add lime juice, chili crisp, or sriracha for a kick.
Serve hot.