Buttermilk ranch dressing

3/4 cup sour cream

1/3 cup buttermilk

2 tbsp mayonnaise

2 tbsp finely chopped dill

1 tbsp finely chopped chives

1 tbsp finely chopped parsley

1 garlic clove, minced

1 tbsp white-wine vinegar

2 tsp Dijon mustard

1/2 tsp salt

1/4 tsp pepper