Trim excess fat from the chuck roast and pat dry with paper towels. Combine kosher salt, black pepper, and smoked paprika and rub evenly all over the roast.

Dredge

Place the cup of all-purpose flour on a plate and lightly dredge the roast, shaking off excess flour. Reserve remaining flour for thickening if desired.

Sear

Heat a heavy Dutch oven or large oven-safe pot over medium-high heat. Add the vegetable oil and heat until shimmering. Sear the roast on all sides, about 4–5 minutes per side, until a deep brown crust forms. Transfer the seared roast to a plate and set aside.

Aromatic Base

Sauté vegetables

Reduce heat to medium. Add the onions, celery, and carrots to the pot and sauté 6–8 minutes until starting to soften and edges brown. Add the minced garlic and tomato paste and cook 1–2 minutes, stirring, until fragrant and tomato paste darkens slightly.

Deglaze

Pour in the red wine (or 1 cup beef broth if not using wine) and use a wooden spoon to scrape up browned bits from the bottom of the pot. Simmer 2–3 minutes to reduce slightly.

Liquids & Aromatics

Build braising liquid

Return the seared roast to the pot, nestling it into the vegetables. Add the beef broth, Worcestershire sauce, bay leaves, thyme sprigs, and rosemary sprigs. The liquid should come about halfway up the roast; add more broth or water if needed. Bring to a gentle simmer on the stovetop.

Braise

Cover the pot with a tight-fitting lid and transfer to a preheated oven at 325°F (160°C). Braise until the roast is fork-tender, about 3 to 3 1/2 hours for a 6-lb roast (check at 3 hours). During the last 60 minutes, add the baby potatoes around the roast so they cook in the braising liquid.

Vegetable Finish (for serving)

Finish vegetables

If using frozen peas, add them to the pot during the last 5 minutes of cooking to warm through. When the roast is done, remove the pot from the oven. Transfer the roast and large vegetables to a carving board and tent with foil to rest 15–20 minutes. Remove and discard thyme and rosemary sprigs and bay leaves.

Gravy Thickening & Finish

Prepare slurry

While the roast rests, strain the braising liquid into a fat separator or skim fat from the top with a spoon. Measure about 4 cups of strained braising liquid into a wide saucepan over medium heat. In a small bowl, whisk the cornstarch with the cold water until completely smooth to make a slurry.

Thicken gravy

Bring the braising liquid to a gentle simmer. Whisk in the cornstarch slurry in a steady stream, stirring constantly until the gravy thickens, 2–4 minutes. If too thin, mix an additional 1 tbs cornstarch with 1 tbs cold water and repeat. If too thick, thin with additional warm broth. Finish by whisking in the butter and chopped parsley for shine and flavor. Taste and adjust seasoning with salt and pepper.

Carve and serve

Slice the roast against the grain into 1/2" slices. Arrange slices on a serving platter with the braised carrots, onions, celery and potatoes. Spoon the hot gravy over the meat and vegetables or serve gravy in a sauceboat. Garnish with additional chopped parsley.