Cut the bread into thin slices, halve the slices. Place them side by side on a baking tray lined with baking paper. Sprinkle with 3-4 tablespoons of oil and bake in a preheated oven (electric cooker: 225 °C/ circulating air: 200 °C/ gas: see
manufacturer) bake for about 10 minutes. Take out of the oven and let cool down.
Meanwhile, for the vinaigrette, peel and finely dice the onions. Heat 4 tablespoons of oil in a small pan, add onions and fry until translucent. Sprinkle with sugar, season with salt and pepper and deglaze with vinegar.
Let simmer for about 3 minutes at low heat. Remove from the heat, pour into a bowl and allow to cool.
Clean and wash the tomatoes and cut the green and red tomatoes into slices. Halve the cherry tomatoes. Wash basil, shake dry and pluck the leaves from the stems. Pluck the mozzarella. Mix tomatoes, bread, basil and mozzarella in a large bowl.
Pour vinaigrette over it, fold in. Let the salad steep for about 5 minutes. Arrange and sprinkle with pepper.