Pre-heat the oven to Gas 3, 160°C, fan 150°C.
Place a large frying pan over a medium heat and add a little of the oil. Season the beef with salt and pepper, and toss the pieces in the flour. Fry in batches until golden brown all over, transferring the meat to a large casserole dish and deglazing the pan with the some of the stock and the Guinness between batches.
Add a little more oil to the pan and brown the onions, carrots and turnips in batches, continuing with the deglazing between batches.
Finally, add the remaining oil to the pan and gently fry the garlic for one minute. Add to the casserole dish, together with the thyme, and stir with a wooden spoon. Pour in any remaining stock - the casserole ingredients should be just barely covered with stock.
Place in the oven and cook for 3-4 hours, until the meat falls apart when pulled with 2 spoons.
*Inspired by Lulu G. featured in the Realfood Cookbook
For top tips on protecting you and your family when preparing raw meat and poultry, visit Food Safety in the Home and view the full Food safety at home video.