To create the base sauce, add the Lee Kum Kee Gluten Free Soy Sauce, Hoisin Sauce, Gluten Free Oyster Sauce and Chilli Garlic Sauce to a jar. Seal and shake well to combine. Place the mince in a bowl. Spoon 3½ tablespoons of the base sauce over the mince and press it out into a thin layer. Sprinkle with the baking soda and cornflour, gently mix to combine and set aside to marinate.
Arrange the tofu slices in a shallow dish in a single layer. Spoon over 4 tablespoons of the base sauce. Sprinkle with 1 teaspoon cornflour, gently turn the slices and sprinkle with the remaining 1 teaspoon cornflour. Set aside to marinate. Heat 2 tablespoons of oil in a large frying pan over medium-high heat. Add the mince and cook in one large piece without breaking it up. Sear for about 2 minutes, turn and cook for another 2 minutes until browned. Break into large chunks, remove from the pan and set aside.
Add 2 tablespoons of oil to the pan. Place the tofu in the pan and sear for about 2 minutes on each side, or until golden. Remove and set aside. Wipe out the pan if needed. Heat 2 tablespoons of oil over medium-high heat. Add the broccoli and leek and cook for 3 minutes, stirring occasionally. Add 2 tablespoons of water, cover with a lid and allow the vegetables to steam briefly.
Remove the lid, add the bok choy and spring onions with another 2 tablespoons of water, cover again and steam for 3 minutes, or until the vegetables are just tender. Return the mince to the pan. Add the ginger and garlic and cook for about 2 minutes, stirring gently, until fragrant.
In the jar with the remaining base sauce, add the vegetable stock, water, rice wine vinegar and cornflour. Shake well to combine.