Preheat oven to 400 degrees. Drain water from tofu and set aside.
While the tofu is draining, mix together the ingredients for the teriyaki sauce and set aside. Once the tofu is finished draining, cut into about 3/4 inch cubes.
In a medium sized dish, let the tofu marinate for about 15 minutes (or longer depending on how much time you have).
Once the tofu is done marinating, place the cubed tofu on a baking pan with the chopped peppers, broccoli, and onions so that they are evenly placed. Place in the oven and cook for 20 minutes, flipping the tofu and veggies halfway in between.