Ba Si Di Gua

Ingredients

• 500 g sweet potatoes
• 800 ml neutral oil, for frying
• 200 g caster sugar
• 2 tbsp neutral oil, for the syrup
• 2 tbsp water
• 1 tsp white sesame seeds (optional)
• 1 tsp neutral oil, for the plate
• 1 large bowl of iced water, to serve

Before you cook

• Peel the sweet potatoes and cut them into 3 cm chunks, rolling the potato a quarter turn between cuts so each piece has angled faces.
• Rinse the chunks to wash off surface starch, then dry them very thoroughly.
• Brush a serving plate generously with oil.
• Fill a large bowl with iced water and set it on the table.

Steps

1. Heat the frying oil to 150C.
2. Fry the sweet potato for 5 to 6 minutes, until a skewer slides in easily.
3. Lift the pieces out onto a rack.
4. Raise the oil to 190C.
5. Return the sweet potato and fry for 90 seconds, until the outside is crisp and deep gold.
6. Drain the pieces and keep them somewhere warm.
7. Wipe out a clean wok and add the 2 tbsp of oil, the sugar and the 2 tbsp of water.
8. Cook over medium-low heat, stirring slowly, for 6 to 8 minutes.
9. Watch for the moment the bubbling quietens, the syrup turns pale amber, and a lifted spoon drips a fine thread.
10. Take the wok off the heat immediately.
11. Tip in the hot sweet potato and turn it fast so every piece is coated.
12. Turn the pieces out onto the oiled plate and separate them with chopsticks.
13. Scatter over the sesame seeds and carry the plate to the table at once.
14. Dip each piece into the iced water for a second so the sugar sets to glass before you eat it.