Icebox Buttermilk Dressing

I found this on Oprah's homepage - it is sooooooo yummy - especially when fresh herbs are used,but even with dried, it is yummy!

Ice Box Buttermilk dressing
1/2 cup extra-virgin olive oil
1/2 cup reduced-fat mayonnaise (I used regular Kraft mayo)
1/2 cup buttermilk
2 tablespoons grainy mustard,(I used 1 tsp dried Coleman's powdered mustard & 1 tsp spicy brown)
1 tablespoon red wine vinegar
2 tablespoons chopped rinsed capers
2 tablespoons minced shallots (I used 2 T onion and 1 very large clove of garlic)
2 teaspoons chopped fresh oregano (I used 1 tsp dried)
1 teaspoon chopped fresh basil (I used 1/2 tsp dried)
1 teaspoon chopped fresh tarragon (I used 1/2 tsp dried)
1 teaspoon sugar
Salt (I used about 3/4 tsp sea salt (medium grain)

Put all ingredients in a blender and whirl until smooth. Keep in refrigerator for up to 1 week, covered.