We had a Mason jar of this in the refrigerator all the time when I was growing up, don't remember the Worcestershire sauce or the vinegar, but I was a kid so. Mom didn't grate the onion or blend it. She put one clove of garlic in whole also. It had to sit in the refrigerator for a week to get the flavors to taste just perfect. She would shake it up a few times a day it was my favorite dressing ever. I'm 64 now and moms been gone 22 years now, and don't know why I thought of it now but was excited to see the recipe.

Just a food for thought, write down favorite recipes your mom makes while she's with you, she made so many good things and have no idea how to make, I regret not paying attention when she cooked, don't make the same mistake I did.