In a medium mixing bowl, combine the olive oil, red wine vinegar, and lemon juice. Whisk until well blended.
Add the Dijon mustard, minced garlic, dried oregano, dried basil, dried parsley, onion powder, salt, and black pepper to the bowl.
If you prefer a slightly sweeter dressing, incorporate the maple syrup or agave nectar at this stage.
Whisk all the ingredients together until the dressing is smooth and emulsified.
Taste the dressing and adjust the seasoning if needed, adding more salt or herbs according to your preference.
Transfer the dressing to a clean glass jar or container with a lid. Refrigerate for at least 30 minutes to allow the flavors to meld.
Before serving, shake the jar well to recombine the ingredients, as they may separate during storage.