parmesan-peppercorn wedge salad

Ingredients

• 1 cup mayonnaise
• 1/2 cup sour cream
• 1/2 cup grated parmesan (not shredded)
• 1/4 cup flat-leaf parsley, minced
• 1 tablespoon sliced green onion
• 1 tablespoon fresh ground peppercorns (try-colored ones are nice)
• 1 teaspoon worcestershire sauce
• 1/2 teaspoon white vinegar
• 1/4 teaspoon kosher salt
• 1 clove garlic, minced
• 1/4 cup buttermilk (or more for desired consistency)
• 1 - head iceberg lettuce, cut into 4 wedges (remove core)
• 1 pound carrots, shredded
• - chopped fresh chives, for garnish