Instructions: 1. Place all the marinade ingredients in a bowl and mix together well. Add the tuna, cover and refrigerate for at least 4 hours.

2. Prepare the salsa. Cut the cucumber in half lengthways, remove the seeds with a spoon, cut each half into thirds and then thinly slice. Cut the red onion into thin wedges. To make the dressing, dissolve the sugar in a little hot water, add the lemon juice and rice wine vinegar and mix together well. In a small bowl, mix together the cucumber, red onion and red chilli. Add the dressing and toss all the ingredients together

3. Mix together the wasabi, natural yoghurt and lemon juice

4. Meanwhile, prepare the rosti. Grate the cold potatoes and mould into 4 balls, flatten slightly. Heat the oil in a frying pan, add the potatoes and cook for 2 to 3 minutes on each side

5. Heat a griddle pan and cook the tuna steaks for 4 minutes on each side, or until just opaque in the centre.

6. Place the rosti on four serving plates, place the tuna steaks on top and arrange a pile of cucumber salsa by the side. Serve with the wasabi sauce.

If you would like to email yourself the recipe for later use, or share the recipe with your friends or family, enter the email addresses below and this recipe will be emailed to you and others as well.