Follow these steps for a perfectly delicious Teriyaki Tofu Stir-Fry:

1. Prepare the Tofu:
   • If you haven’t already, press the tofu. Wrap the block of tofu in several layers of paper towels or a clean kitchen towel. Place it on a plate and put something heavy on top (like a few cookbooks or a cast-iron skillet). Let it press for at least 30 minutes, or up to an hour, changing the paper towels if they become saturated. This step is crucial for removing excess water, allowing the tofu to get crispy and absorb more flavor.
   • Once pressed, cut the tofu into 1-inch cubes.
   • In a medium bowl, gently toss the tofu cubes with 2 tablespoons of soy sauce (or tamari) until lightly coated.
   • Sprinkle 1 tablespoon of cornstarch over the tofu and toss again gently until each piece is evenly and lightly dusted. This will help create a crispy exterior when cooked.
2. Cook the Tofu:
   • Heat 1 tablespoon of sesame oil (or your chosen cooking oil) in a large skillet or wok over medium-high heat. The oil should be hot enough that a piece of tofu sizzles immediately when added.
   • Carefully add the tofu cubes in a single layer, ensuring not to overcrowd the pan (cook in batches if necessary).
   • Cook for 3-5 minutes per side, until golden brown and crispy on all sides. This usually takes about 10-15 minutes in total.
   • Once cooked, remove the tofu from the skillet and set it aside on a plate lined with paper towels.
3. Prepare the Teriyaki Sauce:
   • While the tofu is cooking, or just after, prepare the sauce. In a small bowl, whisk together the 1/2 cup soy sauce (or tamari), 1/4 cup water (or pineapple juice), mirin, brown sugar (or alternative sweetener), rice vinegar, minced garlic, and grated ginger.
   • In a separate tiny bowl, make a slurry by whisking together 1 tablespoon of cornstarch with 2 tablespoons of cold water until smooth. Set this aside.
4. Stir-Fry the Vegetables:
   • Add the remaining 1 tablespoon of sesame oil to the same skillet or wok used for the tofu (no need to clean it). Heat over medium-high heat.
   • Add the sliced red onion and carrots to the hot skillet. Stir-fry for 2-3 minutes until they begin to soften. These harder vegetables need a little more cooking time.
   • Add the sliced bell peppers and broccoli florets. Continue to stir-fry for another 3-4 minutes. You want the vegetables to be tender-crisp – cooked through but still retaining a slight bite and vibrant color.
   • If using shiitake mushrooms and snow peas/snap peas, add them in the last 1-2 minutes of stir-frying the vegetables, as they cook quickly.
5. Combine and Thicken:
   • Return the cooked tofu to the skillet with the vegetables. Gently toss to combine.
   • Give the prepared teriyaki sauce mixture a quick whisk and pour it over the tofu and vegetables. Bring the mixture to a gentle simmer, stirring constantly.
   • Once simmering, give the cornstarch slurry another quick whisk (as cornstarch can settle) and pour it into the skillet.
   • Continue to stir constantly for 1-2 minutes, or until the sauce thickens to a glossy consistency that coats the tofu and vegetables nicely. Be careful not to overcook once the sauce has thickened, as it can become too gummy.
6. Serve:
   • Remove the skillet from the heat. Serve the Teriyaki Tofu Stir-Fry immediately over your choice of base (like steamed rice or noodles).
   • Garnish with toasted sesame seeds, sliced green onions, and/or red pepper flakes, if desired.