3/4 cup mayonnaise
3/4 cup sour cream
1/4 cup buttermilk
1 Tbsp olive oil
1 Tbsp dried parsley
1 tsp dried chopped onion
1 tsp oregano
1/2 tsp mustard powder
1/2 tsp pepper
1/4 tsp garlic powder

Combine all of the ingredients in a blender or food processor until combined. Store in an airtight container in the refrigerator.