Place diced bacon in a pot. Stir-fry for about 7 minutes.
Add chopped onion and leek (wash first, cut off green ends and split remaining white part lengthwise into 4 parts). Stir-fry occasionally for about 5 minutes, meanwhile add olive oil and butter.
Add peeled and diced potatoes, mix and stir-fry together for about 1-2 minutes.
Pour in hot broth, add bay leaf and allspice, bring to a boil. Cover and cook for about 10-15 minutes until vegetables are soft.
Add chopped kale leaves (soft parts of leaves only), cook for about 2-3 minutes.
Add crumbled melted cheese and stir until it dissolves while the soup continues to cook.
Add sour cream and fresh parsley, mix and remove from heat after boiling.