In a small bowl, whisk together yogurt, minced garlic, garlic powder, mustard, lemon juice, salt, pepper, and olive oil until well combined. Then whisk in green onion, tarragon, chives, dill and parsley. Set aside to use with salad.
You must use plain yogurt. Anything flavored, or sweetened with honey will totally throw off the flavor of the dressing. If you prefer, you can use nonfat or low fat yogurt. I just prefer my full fat dairy for the flavor! Additionally, I like to use all fresh herbs in the green goddess dressing. However, if these are not available, dried herbs would work in this dressing for the pasta salad. Start with 1 teaspoon of dried tarragon, chives, dill, and parsley. Then adjust to taste. The dressing can also be made ahead of time, which allows the flavor to really develop and stand out, especially with the dried herbs.