Preheat your oven to 300°F (150°C). Pat the beef brisket dry with paper towels, then season it all over with the kosher salt and freshly ground black pepper, pressing the seasoning gently into the meat.

Heat the olive oil in a large, heavy, oven-safe pot or Dutch oven over medium-high heat. When the oil is hot, add the seasoned brisket and sear for 4–5 minutes per side, until a deep brown crust forms. Transfer the browned brisket to a plate and set aside.

Reduce the heat to medium. In the same pot, add the sliced yellow onion and cook, stirring often, for about 5–6 minutes until softened and lightly golden, scraping up any browned bits from the bottom of the pot.

Stir in the minced garlic and cook for about 30 seconds, just until fragrant, being careful not to let it burn.

Add the beef broth, water, tomato paste, smoked paprika, and dried thyme to the pot. Stir well until the tomato paste is fully dissolved and everything is combined into a smooth, aromatic braising liquid.

Return the seared brisket and any accumulated juices to the pot, nestling it into the liquid and onions. Bring the mixture just up to a gentle simmer over medium heat.

Cover the pot with a tight-fitting lid and transfer it to the preheated oven. Braise the brisket for about 2.5 hours, or until the meat is very tender when pierced with a fork.

Carefully remove the pot from the oven and transfer the brisket to a cutting board. Tent it loosely with foil to keep it warm while you prepare the rice in the same pot.

Skim any excess fat from the surface of the braising liquid if desired. You should have enough liquid to cook the rice; if it looks very reduced, stir in a small splash of water to reach a gentle simmering level.

Stir the rinsed long-grain white rice into the hot braising liquid, making sure the grains are evenly distributed and submerged. Bring the mixture to a gentle simmer on the stovetop over medium heat.

Reduce the heat to low, cover the pot, and cook the rice for about 15–18 minutes, or until the liquid is absorbed and the rice is tender and fluffy. Avoid lifting the lid too often so the steam stays trapped.

While the rice cooks, slice the warm brisket against the grain into thin slices or shred it into bite-sized pieces, depending on your preference.

When the rice is done, turn off the heat and gently fluff it with a fork. Stir in the unsalted butter until it melts and coats the rice, then sprinkle in the chopped fresh parsley and fold it through.

Nestle the sliced or shredded brisket back on top of the hot rice in the pot, spooning some of the onion-rich juices over the meat. Cover and let it rest for 5 minutes so the flavors mingle before serving.

Serve generous scoops of the seasoned rice topped with tender brisket and onions, garnished with a little extra fresh parsley if desired. Enjoy while hot.