1. Prepare the Tofu:
* Drain the tofu blocks. Press them for at least 30 minutes (or up to a few hours in the fridge) to remove as much water as possible. You can use a tofu press or wrap the blocks in paper towels/clean kitchen towels and place something heavy on top.
* Once pressed, crumble the tofu into small, irregular pieces with your hands or a fork. Don’t aim for uniformity; varied sizes create better texture.
* In a medium bowl, whisk together the marinade ingredients: 3 tbsp soy sauce, 2 tbsp rice vinegar, 1 tbsp maple syrup, 1 tbsp sesame oil, 1 tbsp grated ginger, and 2 minced garlic cloves.
* Add the crumbled tofu to the marinade, tossing gently to coat. Let it marinate for at least 20-30 minutes, or longer in the fridge for more flavor.
* After marinating, sprinkle the 2 tbsp of cornstarch over the tofu and toss gently until lightly coated. This will help it crisp up.

2. Make the Nuoc Cham Dipping Sauce:
* While the tofu marinates, prepare the Nuoc Cham. In a small bowl, dissolve the sugar in the warm water.
* Stir in the fish sauce (or vegan alternative), lime juice, rice vinegar, minced garlic, and chili.
* Add the optional shredded carrot. Taste and adjust sweetness, sourness, or spiciness as needed. This sauce can be made ahead and stored in the fridge. The flavors meld beautifully over time.

3. Cook the Tofu:
* Heat 1-2 tablespoons of cooking oil in a large non-stick skillet or wok over medium-high heat.
* Once the oil is shimmering, add the marinated and cornstarch-coated tofu crumbles in a single layer (cook in batches if necessary to avoid overcrowding, which prevents crisping).
* Cook for 8-12 minutes, stirring occasionally, until the tofu is golden brown and crispy on most sides.
* Remove the crispy tofu from the skillet and set aside on a plate.

4. Stir-Fry the Vegetables & Aromatics:
* To the same skillet (add another tablespoon of oil if needed), add the chopped onion and cook over medium heat for 3-4 minutes until softened.
* Add the julienned carrots and bell pepper. Stir-fry for 3-5 minutes until they are tender-crisp.
* Stir in the sliced shiitake mushrooms and cook for another 2-3 minutes until they soften and release their moisture.
* Add the finely minced lemongrass, the additional 3 minced garlic cloves, 1 tbsp grated ginger, and the optional minced chili. Cook for 1-2 minutes more, until fragrant. Be careful not to burn the garlic and ginger.

5. Combine and Finish the Filling:
* In a small bowl, whisk together the stir-fry sauce ingredients: hoisin sauce, 2 tbsp soy sauce, water/broth, 1 tbsp lime juice, and optional Sriracha.
* Return the crispy tofu to the skillet with the vegetables.
* Pour the stir-fry sauce over the tofu and vegetables. Toss everything together gently to coat evenly. Cook for another 1-2 minutes, allowing the sauce to thicken slightly and coat all the ingredients.
* Remove from heat.

6. Assemble and Serve:
* Arrange the washed lettuce leaves on a large platter.
* Place the warm tofu and vegetable filling in a serving bowl.
* Set out small bowls of fresh herbs (mint, cilantro, Thai basil), cooked rice vermicelli noodles (if using), crushed peanuts, lime wedges, and the Nuoc Cham dipping sauce.
* Allow everyone to build their own lettuce wraps by spooning the tofu filling into a lettuce cup, adding their desired herbs and toppings, and drizzling with Nuoc Cham.