Follow these steps carefully to build layers of flavor and achieve the perfect texture for both the tofu and the final filling. The key is in the preparation and the high-heat, quick-cooking process.

1. Press the Tofu: This is the most critical step for achieving crispy tofu. Drain the block of tofu and wrap it in several layers of paper towels or a clean kitchen towel. Place it on a plate and put something heavy on top, like a cast-iron skillet or a few cookbooks. Let it press for at least 30 minutes, or up to an hour. This removes excess water, allowing the tofu to get firm and crispy rather than steamy and soft.
2. Prepare the Tofu for Cooking: Once pressed, unwrap the tofu and crumble it with your hands into small, irregular, bite-sized pieces. The varied shapes and sizes create more surface area for crisping up. In a medium bowl, gently toss the crumbled tofu with 1 tablespoon of soy sauce and 1 tablespoon of cornstarch until it’s evenly coated. The cornstarch will feel dry at first but will adhere to the tofu.
3. Mix the Stir-Fry Sauce: In a small bowl or liquid measuring cup, whisk together all the sauce ingredients: hoisin sauce, water (or broth), soy sauce, rice vinegar, sesame oil, maple syrup, and sriracha (if using). Set it aside. Having the sauce ready is crucial for a fast-moving stir-fry.
4. Cook the Tofu: Heat the avocado oil in a large skillet, wok, or non-stick pan over medium-high heat. Once the oil is shimmering, carefully add the cornstarch-coated tofu crumbles in a single layer. Don’t overcrowd the pan; cook in two batches if necessary. Let the tofu cook undisturbed for 4-5 minutes, until the bottom is golden brown and crispy. Then, stir and continue to cook for another 5-7 minutes, tossing occasionally, until the tofu is browned and crispy on all sides. Transfer the cooked tofu to a clean plate and set it aside.
5. Sauté the Vegetables: In the same skillet (you may add a teaspoon more oil if it’s dry), add the finely chopped onion and cook for 3-4 minutes until it begins to soften. Add the chopped mushrooms and red bell pepper. Cook, stirring occasionally, for 5-6 minutes, until the mushrooms have released their moisture and started to brown and the peppers are tender-crisp.
6. Add the Aromatics: Clear a small space in the center of the pan and add the minced garlic and grated ginger. Sauté for about 30-60 seconds until they become very fragrant. This step, called blooming, infuses the entire dish with their flavor. Stir them into the rest of the vegetables.
7. Combine and Sauce: Return the crispy tofu to the skillet with the vegetables. Add the chopped water chestnuts and scallions. Give everything a good stir to combine. Pour the prepared stir-fry sauce over the mixture. Stir continuously for 1-2 minutes, until the sauce thickens and glazes every piece of tofu and vegetable beautifully.
8. Prepare the Lettuce and Serve: Gently wash and dry the lettuce leaves. Carefully separate the whole leaves to create natural cups. To serve, arrange the lettuce cups on a large platter. Spoon the warm tofu stir-fry filling into a serving bowl. Let everyone assemble their own wraps by spooning the filling into a lettuce cup and adding their favorite garnishes like shredded carrots, chopped peanuts, and fresh cilantro.