Make the mayonnaise base by blending egg yolks with the brine from dill pickles, American mustard, dried dill, onion, and garlic powder. Slowly drizzle in the oil while mixing until fully emulsified.
Add the sour cream along with the seasoning mix and continue blending until smooth and well combined.
Serve this sauce with wedge salad, or enjoy it alongside chicken, French fries, or straight from the spoon.