Heat a cooking pot or saucepan and put-in the butter. Allow the butter to melt.

Add the potatoes, onions, and white onion leeks. Let the vegetable cook under medium heat for at least 8 minutes (stir once in a while for the vegetables to be uniformly cooked).

Add salt and pepper.

Pour-in the chicken stock and let boil. Simmer for 5 to 7 minutes.

Turn-off the heat and allow the mixture to cool. Put the mixture in a blender then hit the liquefy button to make the mixture smooth.

Put the mixture back in the heated cooking pot then add the milk and whipping cream and stir. Cook while stirring for a couple of minutes more.

Transfer to a soup bowl and garnish with minced leeks on top.

Serve. Share and enjoy!