Pat the brisket dry with paper towels. In a small bowl combine kosher salt, black pepper, smoked paprika, garlic powder and onion powder. Rub the spice mixture evenly all over the brisket, pressing it into the meat. Let rest at room temperature 20–30 minutes while you preheat your oven to 300°F (150°C).

Sear

Heat a large ovenproof Dutch oven or heavy skillet over medium-high heat and add olive oil. When shimmering, place brisket fat-side down and sear 4–5 minutes until deeply browned. Turn and sear the other sides 3–4 minutes. Remove brisket to a plate.

Aromatics and Braise

Reduce heat to medium. Add sliced onion to the pot and cook 3–4 minutes until starting to soften, stirring to scrape up browned bits. Add smashed garlic and cook 30 seconds until fragrant. Return the brisket to the pot, nestling it on top of the onions. Pour beef broth around the brisket (not directly on top to preserve seasoning). Add thyme sprigs and bay leaf. Cover with a tight-fitting lid.

Oven Braise

Transfer the pot to the preheated oven and braise until fork-tender, about 2.5–3 hours (time will vary with thickness). Check at 2 hours: the brisket should yield easily to a fork. If liquid reduces too quickly, add up to 1/2 cup more broth or water.

Rest and Chop

Remove the pot from oven. Transfer brisket to a cutting board and tent loosely with foil; let rest 15–20 minutes. Strain and reserve braising liquid and onions. Using two forks or a chef’s knife, chop or shred the brisket into bite-sized pieces (about 1/2–3/4 inch).

Finishing & Serving

Reduce Braising Liquid

Place the Dutch oven or a medium saucepan with the reserved braising liquid and onions over medium-high heat. Bring to a simmer and reduce until slightly thickened, about 5–8 minutes. Stir in apple cider vinegar, brown sugar and unsalted butter; simmer 1–2 minutes to combine. Taste and adjust seasoning with salt and pepper if needed.

Combine with Brisket

Add the chopped brisket to the reduced sauce and toss to coat and rewarm for 2–3 minutes so the meat absorbs flavor. Stir in chopped parsley.

Serve

Serve the chopped brisket hot with tortillas or crusty bread. Offer pickled red onions or quick slaw and hot sauce or BBQ sauce on the side. For sandwiches, pile brisket on bread, spoon extra sauce over the meat, and finish with optional pickles or slaw.