Finely chop the garlic and then sprinkle with 1/4 teaspoon salt. Work into a paste with the side of a chef's knife. Transfer to a medium bowl and add the mayonnaise, buttermilk, parsley, pesto, orange zest, scallions, 1/2 teaspoon of salt and a few grinds of pepper. Whisk until well blended.
Refrigerator in an air-tight container until ready to use or up to 3 days. Garnish with fresh basil leaves if using and serve with cut vegetables and crackers for dipping.
Copyright 2016 Television Food Network, G.P. All rights reserved.