Heat the oil for the filling in a pan and cook the onion until softened.

Add the garlic, curry powder and turmeric, and stir until fragrant.

Add the chicken and cook until the outside is no longer raw.

Stir in the potato, salt, sugar and water, then cook until the potatoes are tender and the mixture is fairly dry.

Mash a few of the potato pieces lightly so the filling holds together better, then let it cool completely.

Put the flour and salt in a bowl, rub in the butter, then mix in the oil and enough cold water to make a smooth dough.

Knead briefly until the dough comes together, cover it and let it rest for 20 minutes.

Divide the dough into 10 pieces and roll each one into a thin circle.

Place a spoonful of filling in the center of each circle and add a small wedge of egg if using.

Fold each piece over into a half-moon, press out any trapped air and crimp the edges firmly to seal.

Heat enough oil in a deep pan for frying and cook the curry puffs in batches until golden brown and crisp.

Drain them on paper towels or a rack and serve warm or at room temperature.