Steam yam until soft, then mash into a paste.

Gradually mix in tapioca flour until the dough is slightly sticky and moldable.

Knead on a floured surface until smooth.

Divide into small pieces and roll into small balls. Press a dent in the centre with your thumb to form an abacus shape.

In a pot of boiling water, cook the abacus seeds. Stir periodically to prevent sticking.

Once they float, cook for 1 more minute.

Scoop out and place into cold water for 2 minutes, then drain and set aside.

Heat oil in a wok over medium heat.

Fry shallots until golden, then remove and set aside.

In the same oil, add garlic and sauté until fragrant.

Add dried shrimp, mushrooms, and black fungus, and stir-fry until aromatic.

Season with salt and add water, then cover and simmer for 5 minutes.

Add the cooked abacus seeds and stir-fry evenly.

Season with white pepper and adjust salt to taste.

Mix in the fried shallots and toss well.

Garnish with spring onions and coriander before serving.