Purple sprouting broccoli tempura with nuoc cham

In a bowl, whisk together the cornflour, plain flour, sesame seeds (if you're using them), and a generous pinch of salt.

Fill a large, deep pan no more than a third full with vegetable oil. Heat the oil until it reaches 180 °C, or until a small cube of bread dropped into it browns in about 20 seconds.

Quickly whisk the soda water into the flour mixture, taking care not to overmix; a few lumps are fine. Using tongs, dunk the purple sprouting broccoli into the batter, ensuring it's lightly coated.

Carefully lower the battered broccoli into the hot oil. Fry for 2–3 minutes, until the tempura is crisp and lightly golden. Drain the cooked tempura on kitchen paper to catch any excess oil, then serve immediately with the nuoc cham on the side for dipping.