Vegetable soup

It is necessary:



150 g of vegetables (carrots, celery, peas, etc..)
300 g potato
1 bouillon cube,
1 egg yolk
3 tablespoons milk
30 g margarine,
tablespoon chopped parsley.

Preparation:
 
The cleaned vegetables, chop, boil in salted water, squeeze and mash.
Then add the grated potatoes and bouillon cube, pour with 1.5 liters of water and salt to taste.
Before serving, stir in soup egg yolk whisked with milk, margarine and chopped parsley.