Ingredients

　　2 teaspoons tarragon vinegar

　　3/4 teaspoon Dijon mustard coarse salt and freshly ground pepper

　　1/2 cup extra-virgin olive oil

　　1/2 cup sour cream

　　2 tablespoons finely chopped fresh tarragon

　　Stir together vinegar and mustard; season with salt and pepper. Pour in olive oil in a slow, steady stream, whisking until emulsified. Stir in sour cream and tarragon.

　　Reprinted with permission from The Martha Stewart Living Cookbook: The New Classics by Martha Stewart Living Magazine, copyright © 2007. Published by Clarkson Potter, a division of The Crown Publishing Group.Buy the full book from Amazon.