Drain the tofu and cut into two-inch cubes. Set aside.
Drain the wood ears, cut off the tough portions and discard (see how). Dice the remaining gelatinous portions.
Pour the soy sauce, mirin and rice wine vinegar into a wide shallow pan. If you want more sauce, add 1/4 cup well-seasoned vegetable broth. Stir in the sugar. Add the peppercorns, bay leaf, grated garlic and ginger. Heat and bring to the boil. Let boil, uncovered, for two to three minutes, or until slightly reduced. Stir in the Sriracha.
Drop in the tofu cubes in a single layer. Scatter the wood ears over the tofu.
Cover the pan, lower the heat and braise the tofu and wood ears for five minutes. Turn off the heat. Leave the tofu and wood ears in the sauce for another 10 minutes.
Drizzle the sesame seed oil over the tofu and wood ears. Sprinkle in the scallions and toasted sesame seeds.
Serve the soy braised tofu and wood ears hot, warm or at room temperature.