Melt butter in a stock pot over medium-low heat. Add potatoes and carrots. Cook until beginning to soften, stirring occasionally, about 10 minutes.
Stir in chopped dill pickles, flour, pickle juice, garlic, Worcestershire, onion salt, sugar, dill, curry powder, and white pepper until well combined.
Add chicken broth, warm milk, and bay leaves. Simmer until vegetables are soft and soup has cooked down, about 1 hour. Season with salt.