In a Dutch oven cook bacon over a medium high heat until desired crispness, remove and set aside on a plate lined with paper towels.
Season beef with salt and pepper.
Add olive oil to Dutch oven over medium heat. Then add stew meat to Dutch oven and brown the beef. When the beef is done remove and set aside.
In the same Dutch oven add the butter and onions, cook until onions are soft and translucent, about 2-3 minutes.
Then add in flour and whisk to make a roux, cook for 1 minute.
Pour in the Guinness beer and whisk until there are no more lumps in the sauce.
Add tomato paste, beef stock, carrots or parsnips, Worcestershire sauce, celery, bay leaves and thyme to the sauce in the Dutch oven. Stir to combine.
Add cooked stew meat, potatoes, and bacon to the Dutch oven. Bring to a boil, then reduce to low, cover and simmer for up to 2 hours, or until sauce has thickened to a loose gravy and vegetables are fork tender.
Taste and add salt and pepper as needed. Remove the Bay Leaves from the stew and serve immediately.