The green bananas provide a starchy, almost potato-like quality to this dish. Dam bong, the liquid from fermented rice, contributes a certain tartness, adding one of the five essential flavours (sweet, sour, bitter, salty and spicy) that the Vietnamese believe should be present in every balanced meal. Street vendors often have big bowls of vinegar or tamarind as additional souring agents at the ready for self service.

4 green bananas

juice of ½ lemon

400 g firm tofu

oil, for frying

3 cm knob of turmeric

1 teaspoon salt

1 tablespoon oil

2 tomatoes, seeded and chopped

1 tablespoon sugar

1 tablespoon dam bong or tamarind pulp

6 betel leaves, cut into thin strips

1 handful perilla leaves, cut into thin strips

Peel off the outer layer of banana skin, leaving a thin layer of skin for texture. Add the lemon juice to a bowl of water. Cut the bananas into batons and put them in the water. This will remove some of the sticky liquid from the bananas.

Meanwhile, cut the tofu into 2 cm blocks. Heat a little oil in a frying pan over high heat and fry the tofu until crisp. Drain well on paper towel.

Using a mortar and pestle, grind the turmeric into a fine paste. Add the salt and oil. Drain the bananas and marinate them in the turmeric mixture for 15 minutes.

Heat a saucepan over medium heat. Add the banana and turmeric mixture and cook for 3–4 minutes, until the bananas have coloured. Add 1 litre of water, the tomatoes and sugar. Reduce the heat and simmer for 10 minutes. Add the dam bong and cook for 2 minutes. Add the fried tofu, betel leaf and perilla and carefully stir to combine.

Serve as part of a banquet with rice or noodles.