Pour half the oil into a shallow dish and place the bread slices in it, pressing with your fingers on one side, then the other. Place on a baking tray and bake in a pre=heated oven at 180⁰C – Gas 4 until crisp. Remove from the oven, and while the bread is still hot rub one side of each slice with the garlic.
Put the tomatoes in a mixing bowl, shred the basil leaves by hand and sprinkle over them; add the onions and olives, then season with salt and pepper. Top each slice with the mixture, drizzle with oil, garnish with basil leaves and serve.