Instructions:
- Pat the beef cubes thoroughly dry with paper towels. Season liberally with salt and pepper.
- Optional Searing: Heat an oven-safe skillet over medium-high heat. Sear the beef cubes in batches until nicely browned on all sides. Transfer seared beef to the slow cooker.
- Prepare the Garlic Butter Rub: In a small bowl, thoroughly mix the softened butter, minced garlic, flour, thyme, rosemary, salt, and pepper until it forms a thick, fragrant paste.
- Coat the Beef: Rub the garlic butter mixture evenly over all the beef pieces in the slow cooker.
- Add Liquids & Aromatics: Scatter the chopped onions and potatoes around and over the beef. Pour the beef stock and Worcestershire sauce over everything. Do not stir vigorously.
- Slow Cook: Cover the slow cooker. Cook on Low for 6–8 hours or High for 3–4 hours, until the beef is fork-tender.
- Final Check & Thicken (If Needed): Once cooked, give the contents a gentle stir. If the sauce is too thin, mix 1 teaspoon of cornflour with 1/2 cup of the liquid, microwave until smooth, and stir back into the crockpot.
- Rest and Serve: Let stand for 10 minutes before serving directly from the crockpot with crusty bread.