The sweetness of caramelized onions gives Rach's easy beef brisket tons of flavor. She also loves to use leftovers to make brisket ragu.
For a complete holiday feast, Rach likes to serve this with her Zucchini-Potato Latkes with Za'atar + Butternut Latkes and Bitter Greens Salad.
In a large cast iron skillet or large cast iron enamel Dutch oven over medium-low to medium heat, caramelize the onions: melt butter, add onions, season with bay, salt and black pepper and white pepper, thyme, cook to golden and soft, 25 minutes, then add sherry if using and remove to bowl.
Meanwhile, bring meat to room temperature. Season liberally with salt and pepper.
Preheat oven to 325˚F.
Return skillet to medium-high heat with oil, 2 turns of the pan. Brown meat 5 minutes on each side, then top with caramelized onions, add the broth and melt in the demi-glace or bouillon and add Worcestershire. Cover pan with heavy foil or lid and bake 3 to 3½ hours to very tender, then slice and serve.