Add the carrots and onions to the slow cooker, then add 3 tbsp of cornflour and stir to ensure an even coating. Rub a little oil all over the beef and season well with salt and pepper. Sear the beef all over in a hot pan, and transfer to the slow cooker.
Add the beef stock, red wine, tomato puree and sugar, ensuring that the beef is mostly covered by the liquid. Cook on low for 5 hours, or high for 3 hours. Once cooked, remove the beef from the slow cooker and cover with foil to keep warm. Rest the beef for up to 30 minutes. If you want to be sure about cooking times, use a meat thermometer - one is linked in the equipment list.
Reduce the remaining liquid and vegetables in the slow cooker to a gravy consistency, adding 3 tbsp of cornflour to thicken (remove a little liquid, mix in the cornflour to make a paste, and mix it back into the gravy). If you've got a slow cooker with a metal pot (see the equipment list for a recommendation) you can do this by transferring it straight to the hob, if not, you'll need to transfer the contents of the slow cooker to a pan.
When you're ready to serve, slice the beef with a sharp knife and coat with plenty of red wine gravy!
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Notes
Cooked Beef Internal Temperature
Insert the beef thermometer into the middle of the beef and wait for the temperature to settle. Use the following temperatures as a guide, depending how you like your beef to be cooked:Rare: 50C Medium: 60C Well done: 70CThe temperature will continue to rise slightly once the beef is removed from the slow cooker.
Resting Beef
For best results, cover with foil and rest the beef for thirty minutes once cooked. This is the perfect time to make your gravy!