In a medium bowl, whisk together mayonnaise, olive oil, and white vinegar until smooth and creamy.
Stir in garlic powder, onion powder, oregano, basil, parsley, thyme, paprika, salt, and pepper. Add Dijon mustard and Parmesan if using and mix until fully combined.
For a smoother texture, blend in a blender or food processor until fully emulsified.
Transfer to a jar or airtight container and refrigerate at least 1 hour before serving to allow flavors to meld.
Serve over salads, use as a dipping sauce, or spread on sandwiches.