Add the olive oil and melt the butter in a large Dutch oven over medium to medium high heat.
Add the sliced onions and a generous pinch of salt. Saute them, stirring often until the onions are a deep golden brown color. This can take 30-40 minutes. If the onions are browning too quickly, reduce to medium heat.
Add the sherry vinegar and use a wooden spoon to scrape the brown bits off the bottom of the pan. Then add in the minced garlic and fresh thyme. Cook for another minute, stirring often.
Pour in the Worcestershire sauce, beef broth, water, and pasta. Stir and bring to a boil over high heat. Then reduce heat to medium and cook until some of the broth has cooked off and the pasta is al dente according to package directions. Stir occasionally.
Stir in the dairy free cheese until melted. Season to taste with freshly cracked black pepper and kosher salt, and enjoy!