Marinate the beef: Place 200g beef slices in a bowl. Add 1 tbsp rice wine, 1 tbsp light soy sauce, 1 tbsp oyster sauce, 1/4 tsp sugar, 1 tsp black pepper powder, 1/2 tbsp flour and 1 tbsp cooking oil. Mix thoroughly until every slice is evenly coated.
Mix the sauce: In a bowl or measuring jug combine 2 tbsp light soy sauce, 1 tbsp dark soy sauce, 1 tbsp oyster sauce, 1 tsp sugar, 1 cup water, 2 tbsp flour, salt to taste and black pepper to taste. Whisk thoroughly until the sauce is completely smooth with no lumps remaining. Taste and adjust seasoning.
Prepare the tofu and mushrooms: Cut 300g tofu into cubes roughly 1.5-2cm thick. Trim the woody roots from 80g enoki mushrooms and separate into smaller clusters.
Sauté the aromatics: Heat a drizzle of cooking oil in a wide deep pan or clay pot over medium heat. Add 3-4 minced garlic cloves, 1 tbsp chopped spring onion and 2 tbsp chopped onion. Sauté for 1-2 minutes, stirring frequently, until softened.
Layer the tofu and mushrooms: Arrange the 300g tofu cubes and 80g enoki mushrooms in an even layer over the aromatics. Give the sauce one final whisk then pour it evenly over the tofu and mushrooms. Place the lid on and bring to a gentle simmer over medium heat.
Add the beef: Place the marinated beef slices in a single even layer. Place the lid back on and braise over medium heat until the beef is just cooked through and tender. Remove from heat immediately.
Garnish and serve: Scatter finely chopped spring onion, chopped red chilli and roughly chopped coriander generously over the top. Serve immediately with steamed white rice.