Preheat the oven to 170`c. Brush 4 filo squares on both sides with melted butter and use to line 4 individual quiche moulds, 10cm in diameter and 3cm deep. Next, layer another 3 sheets of filo on the top of the base layer, brushing the top of each one with butter and staggering them, so the points of each square are 2cm from the one below. Place an empty similar-sized quiche mould inside each filo-lined mould and press very lightly. Bake the croustades for 10minutes. remove the empty moulds as soon as they come out of the oven, then delicately lift the croustades out of their moulds and place them on a wire rack. Sprinkle both sides of the tuna steak with cracked white pepper and pat down with flat of a chef’s knife. Lightly salt the tuna. Heat the oil in a pan and 30g butter over a medium high heat. Add the tuna and sear for 1 minute on each side for rare or 2 minutes for medium. For the salad, whisk olive oil and season with salt and pepper and dress the mixed salad leaves. Place the croustades on individual plates. divide the salad leaves, tomatoes, olives and hardboiled egg between them. Cut the tuna steak slightly on the bias into 4 slices and place a slice on top of each salad and serve immediately.