In a medium mixing bowl, whisk together mayonnaise, Greek yogurt, Parmesan cheese, olive oil, lemon juice, Dijon mustard, garlic powder, salt, and black pepper until smooth and creamy.
Taste and adjust seasonings, add more lemon juice for brightness, Parmesan for richness, or pepper for extra bite.
Transfer to a jar or airtight container and refrigerate for at least 30 minutes before serving to allow the flavors to blend.
Use as a salad dressing, dip, or spread for sandwiches and wraps.