In a large bowl, toss the cubed beef chuck roast with the flour, 1 teaspoon of salt, and 1/2 teaspoon of black pepper until the meat is evenly coated.

Heat the olive oil in a large skillet over medium-high heat. Add the beef in a single layer and sear until deeply browned on all sides (about 4-5 minutes). Do this in batches if necessary. Transfer the browned beef to your slow cooker.

In the same skillet, add the chopped onion and sauté for 3 minutes. Add the minced garlic and tomato paste, cooking for 1 more minute until fragrant. Scrape this mixture into the slow cooker.

Add the halved potatoes, chopped carrots, beef broth, Worcestershire sauce, thyme, and rosemary to the slow cooker. Stir gently to combine.

Cover and cook on LOW for 7-8 hours, or on HIGH for 4-5 hours, until the beef is incredibly tender and easily shreds with a fork.

Remove and discard the herb stems. If you prefer a thicker gravy, whisk 2 tablespoons of cornstarch with 2 tablespoons of cold water, stir it into the stew during the last 30 minutes of cooking.

Taste for seasoning, adding more salt and pepper if needed. Serve hot in deep bowls, garnished with fresh parsley and crusty bread for dipping.