Peel the onion and chop finely. Wash the tomatoes and also dice them. Wash the cucumber, cut in half and scrape out the core with a spoon. Now cut the cucumber halves into thin slices. Put the chopped vegetables in a large salad bowl and season with three tablespoons of olive oil, oregano, salt and pepper.
Pluck the basil leaves. Cut the bread into cubes with an edge length of approx. 2 cm. Dry the cubes in a hot pan for about three minutes without oil, turning them. Then add four tablespoons of olive oil to the pan and toast the bread on medium speed until it becomes crispy.
Peel a clove of garlic, chop it finely and add it to the pan with the bread shortly before the end. Put the crispy bread from the pan in the salad bowl, add the basil leaves and mix everything well. Serve immediately.