2) Place the coated tuna steak on a hot griddle and sear for 2 to 3 minutes so it is still pink inside.
3) Serve the tuna with vegetable tempura and sweet chilli sauce.
For the tempura:
1) Mix together the flour with the cornflour and slowly and mix in the sparkling water.
2) Thinly slice the carrot, onion, red pepper, potatoes and courgettes, and mix together in a bowl. Pick up a handful of the mixed vegetables and squeeze the water out. With the other hand pick up some flour and lightly dust the vegetable parcel to aid the batter sticking.
3) Dip the parcel in the batter mix and very carefully place it in heavy-bottomed pan of hot oil to fry for 3 to 5 mins until the batter is crispy.
To make the sweet chilli sauce:
1) Combine the chilli, sauce, sugar, honey and white wine vinegar in a small pot and reduce for a few minutes.