Heat olive oil in a large skillet over medium-high heat.
Season the roast with salt and pepper, then sear on all sides until browned.
Prepare the Slow Cooker:
Place chopped onions and minced garlic at the bottom of the slow cooker.
Add the seared roast on top.
Add Vegetables and Seasoning:
Add carrots and potatoes around the roast.
Stir together beef broth, tomato paste, thyme, and rosemary, then pour over the roast and vegetables.
Cook the Roast:
Cover and cook on Low for 8–10 hours or High for 4–5 hours, until the meat is tender and shreds easily with a fork.
Serve:
Remove the roast and vegetables from the slow cooker. Slice or shred the beef as desired.
Garnish with chopped parsley if desired and serve hot with the rich cooking juices.
