Cut the leek and parsnip in small pieces.
Put the vegetables, rosemary and freshly squeezed lemon juice in a saucepan filled with the water. Cook for about 30 min.
Take out the sprig of rosemary, cut it finely and put it back in the soup.
Mix everything with an electrical mixer to make a creamy soup.
Add the milk and continue cooking for 1 to 2 minutes. Mix everything well.
Depending on your taste and preference, season in your plate with a few drops of lemon and lemon pepper.