- ¼ cup unsalted butter
- 3 yellow or white onions, thinly sliced
- 2 teaspoons sugar
- ¼ cup sherry vinegar
- ½ cup dry white wine
- 1 pound rigatoni
- 4 sprigs fresh thyme, plus extra for garnish
- 4 cups beef broth
- Kosher salt and freshly ground black pepper
- 1 teaspoon Worcestershire sauce
- ½ cup Parmesan, grated, plus more for serving
- ½ cup heavy cream
- In a large Dutch oven or heavy-bottomed pot, melt butter over medium heat. Add onions and cook until they begin to look translucent. Turn heat down to medium-low, then add in sugar and a generous pinch of salt. Continue to cook, stirring occasionally, until onions are golden brown and caramelized, 30 minutes.
- Pour in sherry and wine to deglaze. Using a wooden spoon to scrape off any bits at the bottom of the pot.
- Turn heat up to medium-high and add rigatoni, thyme, beef broth, Worcestershire sauce, a pinch of salt, and a couple good cranks of black pepper to the pot. Mix well and bring to a boil.
- Give the pasta mixture a mix, then turn the heat down to medium-low. Simmer, covered, until the pasta has absorbed the liquid, 10 to 12 minutes.
- Remove pot from heat. Fish out the thyme and discard. Add Parmesan and heavy cream and mix until pasta is glossy and well-coated.
- Divide pasta among bowls and serve topped with more Parmesan cheese and thyme leaves.