Make the marinade by mixing together the sugar, salt, soy sauce and cornflour slurry. Mix in the pork, let marinate for 15 minutes.
Heat a frying pan with 1 tablespoon oil over high heat. Stir-fry the shallots and garlic until aromatic and brown, about 2-3 minutes. Add the pork and stir-fry until cooked through, about 3-5 minutes. Set aside.
Using the same frying pan, add the oil and heat over high heat. Stir-fry the onions with salt until soft, about 2-3 minutes. Add the baby corn and water chestnuts and stir for 1 minute. Add the pork and enoki mushrooms and stir-fry for an additional 1-2 minutes. Sprinkle over the black bean garlic sauce, oyster sauce, sugar, chilli oil and 1-2 tablespoons of water. Stir to combine. Garnish with a few chopped spring onions, if desired.
Black bean garlic sauce and hot chilli oil can be found in Chinese/Oriental speciality stores.