After soaking beans overnight, cook beans until soft. Drain the beans and put aside two teaspoons of whole beans. Make puree out of all other beans using blender (or whatever you use). Finely mince onion, garlic and bacon. Melt lard in a cooking pot and sauté onion until translucent. Add garlic and bacon and sauté it not more than 2 minutes. Add flour and brown it but not too much. Add cold water and make creamy liquid. Add hot and sweet paprika and stir. Add beans puree and whole beans, stir. Add bay leaf and vinegar; season with salt and pepper. Add water and cook about 45 minutes. Before serving taste the soup, if it is not sour you may drop few drops of vinegar (if you do cook for more 5 minutes). Add sour cream and parsley leaves and serve.