Prepare the sweet potato leaves by breaking the base of the stem and pulling out the fibrous outer layer(It is an option). This should leave you with the leaves and the tender stem parts. You can also clean it by rinsing it with water.
Fill a cooking pot with water and bring to a boil.
Once it boils, stir in salt and oil.
Place the sweet potato leaves in the boiling water and blanch for only 20 seconds. Then, drain the leaves. Do not overblanch the leaves or else they will lose their crunch and become mushy.
Prepare the garlic. You can crush or roughly chop the garlic.
In a pan or wok, add the oil.
Once the oil is hot, stir-fry the garlic and fermented black beans until fragrant.
Turn the heat to high, add the sweet potato leaves, and give it a good mix.
Season with salt, chicken bouillon powder, and oyster sauce.
Mix the seasonings by rotating the leaves and stir-frying quickly.
Adjust the seasoning to taste if needed.
When the leaves are tender, transfer them to your serving plate.