Caramelize the onions

• Melt the butter in a large pot, add the sliced onions and salt.
• Cover and cook over medium heat for 5 minutes.
• Uncover and stir occasionally until the onions are caramelized, adding a splash of water every few minutes and scraping up the brown bits.

Deglaze and add the aromatics

• Deglaze the pot with the white wine.
• Add the thyme.

Cook the pasta

• Add the pasta and pour in the beef broth to cover it.
• Stir in the Worcestershire sauce and bring to a boil.
• Stir occasionally until the pasta is cooked, covering the pot for a few minutes if the liquid evaporates too quickly.

Finish with cream and Parmesan

• Remove the pot from the heat.
• Stir in the heavy cream and a generous amount of Parmesan cheese.
• Serve immediately.