Clean, wash and drain the spring onions. Cut off the white of the spring onions and cut into fine rolls. Cut the green part of the spring onion lengthwise into thin strips. Place in a bowl with ice cubes and cold water
Peel and coarsely chop the garlic. Whip cream until semi-stiff. Puree beans, white spring onion rings and garlic. Season to taste with salt and pepper. Fold in cream in streaks. Spread the bean cream in 4 small glasses and chill
Chop the tomatoes finely. Wash the basil, dab dry and cut the leaves into strips. Whisk milk, egg, some salt and pepper. Stir in olives, tomatoes and basil. Cut the rind off the white bread and cut each slice into 4 strips. Place them side by side on a plate and spread the egg milk with the olives and tomatoes on top
Heat olive oil in a large frying pan. Place the bread strips in the pan with the uncoated side down first and fry until golden brown. Turn the bread carefully, flatten it a little and fry it until crispy brown, even from the coated side. Remove from the pan immediately, allow to cool slightly and place one tamezzini croûton in each glass. Garnish with spring onion curls. Add the rest of the tamezzini