Steam or boil clams until they open. Remove clams from shells and reserve the clam juice. Set clams aside.

In a large pot, combine minced russet potato and chicken stock. Bring to a boil and cook until potatoes are soft, about 15 minutes.

Using an emulsion blender, blend the potato and stock mixture until smooth.

Add Yukon potatoes, carrots, clams, salt, and pepper to the pot. Add enough clam juice and chicken stock to cover the ingredients.

Bring to a simmer and cook for 20 minutes, stirring occasionally.

Stir in heavy cream and butter. Heat through and serve.