http://www.foodnetwork.com/recipes/food-network-kitchen/blue-cheese-dressing-recipe-2011347
In a medium bowl, whisk together the mayonnaise, 1/4 cup blue cheese, half and half, sour cream, lemon juice, Worcestershire, and salt, until smooth. Gently stir in the remaining 1/4 cup blue cheese and season with pepper to taste. Use now or store in the refrigerator for up to 3 days.