Dice the spring onions, reserving the green parts for the garnish
Dice the mushroom very finely.
Stir fry the mushrooms and white parts of the spring onion in the oil until the mushrooms have stopped reducing in size (about 6-7 minutes). Set aside, keeping the oil in the pan.
Stir fry the garlic and ginger in the same oil for a few minutes.
Add the stir fried mushrooms, chilli flakes, chilli bean paste, and fermented black beans to the garlic and chilli. Cook for a few more minutes.
Add the vegetable stock, Shaoxing wine (or dry sherry), and black vinegar (or balsamic), sugar, and soy sauce.
Bring to a boil then reduce to a simmer.
Add the ground Sichuan pepper.
Simmer for 10 minutes.
Dice up the greens of the spring onions.
Add the spring onion greens and half the cornstarch paste and stir well until the soup starts to thicken a little (a couple of minutes). Add the rest of the cornstarch and cook for a little longer if the sauce is not thick enough. Remove from the heat.
Eggplants
Poke the eggplants multiple times with a toothpick. This stops them exploding when being grilled.
Char the eggplants on all sides over a grill. The skins should be blackened. Charing under a very hot broiler would also work. A real bbq, if you have one, grill adds a nice smokiness.
Allow to cool a bit then peel off the skins.
Lay on a serving plate then drag a fork through the eggplants length ways. This is to break them up a little so that the sauce coats more of the eggplant.