Heat a griddle pan until it gets really hot then put your asparagus in it. Place
a heavy saucepan on top so that it presses the spears right down on to the bars.
Cook them for 2 minutes, turning them halfway through, until they have lovely
charred marks. Pop the asparagus on a board and chop them in half at an
angle.
Put the asparagus in a bowl with your tomatoes, half the basil
leaves, the olives, a splash of oil and a squeeze of lemon juice. Season, then
toss it all together and put it to one side while you get the fish
ready.
Rub your tuna steaks with a little bit of oil and season them.
Sear them for about a minute on each side in the griddle pan for a rare steak –
leave them for 2 minutes on each side if you prefer them cooked medium, or 3 to
4 minutes each side if you like them well done.
Pound the remaining basil
in a pestle and mortar then mix in the crème fraîche. Season and add some more
lemon juice to taste.
Put the salad on a plate, then tear the tuna into
strips and pop them on top. Spoon over some of the crème fraîche sauce and
scatter over the baby basil leaves.