Drain the tofu and press it to remove excess water (you can use a tofu press or wrap it in a clean towel and place something heavy on top for 20 minutes).
Cut the tofu into half so you have 2 rectangular blocks. You would need about 2 tofu blocks.
In a big glass container, combine all ingredients needed for the marinade and whisk until well combined. Place the tofu blocks in the container and coat them with the sauce evenly. Let it marinate for 24 hours for maximum flavour.
Preheat oven to 220C. Place the tofu blocks on a baking tray with grease paper. Spoon some of the marinade over and bake for about 20 minutes, flipping halfway.
While char siu is baking, you can make the noodle soup: add water to a pot, ginger slices and bring to a boil. Add mushroom powder, shaoxing wine, soy sauce, white pepper, sweetener, sesame oil and salt.
Add you noodles in and cook according to package instructions. Take the noodles out, keeping the soup on flame. You can also boil the wontons in the same broth.
Glaze the tofu with the marinade and grill for 5 minutes. Repeat this process one or 2 more times to really soak in the flavour.
Slice the tofu char siu. Assemble noodles and pour soup over. Place tofu char siu, greens and steamed wontons. Garnish with spring onions and chili oil.