For the pesto, roast the pine nuts in a dry pan without fat until golden brown, take them out. Coarsely chop the cheese. Wash the basil, shake dry and chop the leaves. Peel the garlic cloves.
Coarsely puree all ingredients with oil in an electric chopper. Season to taste with salt and pepper.
For the salad, peel the onion and cut into fine strips. Wash the tomatoes. Cut the beef tomatoes into slices, cut the cherry tomatoes in half. Wash basil, shake dry. Cut mozzarella into pieces.
Arrange on plates with tomatoes and onion. Mix lemon juice and oil, season with salt and pepper and drizzle over the salad. Add the pesto. Sprinkle salad with basil leaves. Ciabatta tastes good with it.