In a nonstick skillet, pour a tablespoon of extra virgin olive oil and add butter. Soften it over medium heat and add the sliced onion.
Stir it quickly and cover it with a lid to soften slowly and cook in its juices. It will take approximately 15 minutes for the onions to reduce and become golden brown. Stir it every now and then, to prevent them from sticking to the bottom
Add sugar, salt, pepper, and one more tablespoon of extra virgin olive oil. Stir it frequently and don’t go far from the stove, because this is a crucial step to make a perfect soup. This will take approximately 20 minutes.
It’s done when the onion is mellow, dark brown, silky, and almost stringy.
Pour in the beef broth and add bay leaves and thyme. You can add whole branches of it or chop it like I did.
Simmer it slowly for about half an hour with a lid on. The soup should be creamy, not too dense or watery.
Take out bay leaves and herb branches and check out if you need more salt and pepper.
Add a splash of Worcestershire sauce for more umami flavor and apple cider vinegar for acidic relish.