In a large skillet, warm the oil over medium heat. Add the shallots and sprinkle with salt; cook for 3 minutes. Add the pepper, garlic cloves and lemon grass to a food processor and pulse until finely chopped. Transfer the mixture to the skillet and continue to cook for another 3 minutes.
Add the mushrooms to the food processor and pulse to finely chop. Transfer the chopped mushrooms to the skillet and cook for 5 minutes, or until lightly browned. Break the tofu into pieces in the food processor and then pulse until crumbles form. Add the tofu crumbles to the skillet and cook for 5 more minutes.
Meanwhile make the dressing by rinsing out the food processor and adding all of the ingredients to it. Blend until smooth. Pour the dressing into the skillet and stir until everything is evenly coated. Cook for another 10 minutes, until most of the liquid has absorbed.
Spoon the warm tofu mixture into the lettuce leaves and garnish with mint and cilantro before serving.