Tear the basil leaves and chop them up with scissors.
Peel the onions and chop them and the zucchini into thin slices.
Break the eggs into a bowl and whisk them so that they break up. Mix in the chopped basil with a spoon.
Sauté the onions in butter in the soup pot for a few minutes, then add the zucchini. Continue frying until they are soft.
Grate the parmesan onto a plate.
Add the chicken or vegetable stock to the pot, bring it to a boil and let it simmer for twenty minutes.
Mix in the grated parmesan into the basil-egg mixture.
Purée the soup with a hand blender.
Mix the soup with a whisk while the adult pours in the egg mixture.
Grind in some black pepper according to your taste.
Taste, and add salt if needed. 

Dice the bread slices for the croutons.
Coat the diced bread in olive oil in a bowl, then place them in an even layer on a baking tray or pan.
Roast the croutons in a 475-degree oven until they are crisp, place them in a bowl and serve. You can also fry the croutons in a pan.

Instructions:
The recipes in SousChefCooking.com are divided into different work stages and color-coded:

The tasks in red are suitable for children – the sous chefs.
The tasks in black are for the adults.
Tasks in green are intended to be performed together.