Add the mayonnaise, sour cream, chopped dill, chopped chives, garlic powder, onion powder, MSG (if using) and salt and pepper and whisk well to combine.
Taste now to see if you think it needs more salt and pepper. I typically go heavy on the pepper.
You can stop now (without the buttermilk) if you want more of a mayonnaise like consistency to spread on sandwiches.
Add buttermilk a little bit at a time and whisk until you reach the right consistency. I usually only need about 3 tablespoons to hit a thick dressing stage but if you\'re making this for salads, you might want to add more.
Store in a jar or container with a lid in the refrigerator for no more than 2 weeks.
Notes:
If you want this to be more of a spread like mayonnaise, you can omit the buttermilk entirely. This is great Ranch that you can use for a dip for chips, use it on a salad or if you live in the Midwest, you can put it on anything.