Prep: Slice the tofu in half lengthwise, then quarter each “slab” and cut into triangles (you can also just cube the tofu, but I prefer triangles for pan-frying).
Make the Sauce: Add the soy sauce to a large jar or glass measuring cup along with the peanut butter, rice vinegar, sugar, sriracha, water, and cornstarch. Give everything a good whisk, until the sugar dissolves into the liquid. Set aside.
Cook the Tofu: Using one of the following methods
Pan-Fry (less dishes): Warm a wok or large sauté pan over medium heat and add 1 tablespoon of oil, or enough to lightly cover the base of the pan. Add the tofu and cook for 5 to 7 minutes on each side, until crispy. Remove from the pan, sprinkle lightly with salt, and set aside. Add 1 additional tablespoon of oil and proceed with step 2.
Air Fry (faster prep): Line the basket of your air fryer with parchment paper and arrange the tofu so it does not touch. Lightly spray the tofu with cooking spray and a sprinkle of salt, then flip and repeat with the other side. Air Fry at 415F for 10 to 15 minutes, or until the tofu is golden. While the tofu cooks you can warm a work or large sauté pan over medium heat and add 1 tablespoon of oil, then proceed with step 2
Aromatics: Add the ginger, garlic, and white portions of the green onion to the preheated pan and sauté for 30 to 60 seconds, until fragrant.
Stir Fry: Add the bell pepper, carrot, and broccoli stems and cook for 3 to 5 minutes, until the bell pepper is tender. Add the broccoli florets, and sauté for an additional 3 to 5 minutes, until bright green.
Make it Saucy: Add the cooked tofu to the pan with the veggies. Give the stir fry sauce one final whisk to re-incorporate the cornstarch, then pour it over the tofu. Mix well and sauté for an additional 2 to 3 minutes, until the sauce has thickened and the tofu is cooked to your liking.
Serve & Store: Serve the warm stir fry over cooked rice or noodles and top with the reserved green onion and chopped peanuts. Store any leftovers in the refrigerator, in an airtight container, for up to 5 days.