In a dutch oven cook bacon over a medium high heat until desired crispness, remove and set aside
Season beef with salt and pepper. Add olive oil to dutch oven and brown the beef, remove and set aside.
Add butter and onions, cook until onions are soft and translucent, 2-3 minutes.
Add in flour and whisk to make a roux, cook for 1 minute.
Pour in Guinness and whisk until there are no more lumps
Add tomato paste, chicken stock, carrots or parsnips, Worcestershire sauce, celery, bay leaves and thyme, stir to combine. Return beef, potatoes and bacon to the pot
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 bay leaves and enjoy.