Season the roast: Pat the beef dry. Rub all over with salt, pepper, and garlic powder (or minced garlic). Let it sit while you prep the veggies.
Prep the slow cooker: Add the onions, carrots, and potatoes to the bottom.
This creates a bed for the roast and keeps the vegetables flavorful and intact.
Sear the beef: Heat oil in a large skillet over medium-high. Sear the roast 3–4 minutes per side until deeply browned. This step builds flavor and helps the roast stay juicy.
Build the braising liquid: Reduce skillet heat to medium.
Stir in tomato paste and cook 1 minute. Add Worcestershire sauce and beef broth, scraping up browned bits. Pour this mixture over the vegetables in the slow cooker.
Add herbs and roast: Place the seared roast on top of the vegetables.
Add thyme, rosemary, and bay leaves. Cover with the lid.
Cook low and slow: Cook on Low for 8–10 hours or High for 4–5 hours, until the beef is fork-tender and easily shreds.
Taste and adjust: Remove the herbs and bay leaves. Taste the juices and add more salt or pepper if needed.
Make a quick gravy (optional): Transfer 2 cups of the cooking liquid to a saucepan.
Bring to a simmer. Stir together cornstarch and cold water, then whisk into the liquid. Cook 1–2 minutes until thickened.
Season to taste.
Serve: Slice or shred the roast. Spoon over vegetables and gravy. Garnish with parsley if you like.