Place the potatoes in a pan of cold salted water. Bring to the boil and simmer until tender. Once cooked, drain and allow to cool.
Peel and finely dice the shallot. Cut the cherry tomatoes in half. Wash and spin the salad leaves in a salad spinner.
For the aioli: peel and mince the garlic. Place the egg yolk, garlic, lemon juice and salt in a bowl. Whisk together and then start adding the olive oil a little at a time. Keep whisking until all of the olive oil has been incorporated. Check the seasoning and add more lemon juice and garlic if required.
Crush the potatoes with a fork and mix through the aioli. Check the seasoning and adjust if necessary.
Season the tuna steaks with salt and pepper and brush with olive oil.
Heat a griddle pan until hot and then cook the tuna for 2 minutes on each side.
Mix together the juice of 1 lemon and 75ml olive oil. Season with salt and pepper.
Toss the salad leaves, tomatoes and shallot through the lemon juice and olive oil dressing.
Smear a spoonful of tapenade on to the tuna steak.
To serve: fill a stainless steel serving ring with the crushed potatoes. Place a tuna steak on top and finish with a handful of salad leaves.
«The tuna steaks should be pink in the middle - be careful not to overcook.»