In a container or jar with a lid, combine the olive oil, vinegar, onion, lemon juice, honey, Parmesan, Italian seasoning, mustard, Worcestershire sauce, salt, and pepper.
Cover and shake well to combine. This will keep for 1 week sealed in the refrigerator. Shake well before pouring it over the salad.
Notes
Most Italian seasoning is made from a combo of dried oregano, thyme, basil, and rosemary, sometimes marjoram. If you don’t have it, you can use a teaspoon of any combination of those herbs. Basil and oregano are the two must-have herbs in Italian dressing. Marjoram is another good addition. You can mix and match the herbs in equal proportions, but just make sure the total amount is around 1 teaspoon for this recipe.