In a large skillet over medium high heat, quickly sear the roast (for 30 seconds to 1 minute per side).
Place chopped onion in a slow cooker then place seared roast on top.
In a medium bowl, whisk together remaining ingredients (apple juice through salt) till fully combined; pour over roast in slow cooker.
Cover and cook on LOW for 8 to 10 hours or until beef is fork-tender.
Notes
SERVING SUGGESTION: Steamed broccoli spears and Faux-Tay-Toes (steam cauliflower till tender; drain; mash with a little ghee (or olive oil) and salt and pepper to taste till you get a mashed potatoes texture).