Preheat the oven to 350 degrees Fahrenheit

Generously season the pieces of beef with salt and pepper.

Heat the olive oil in a pot on medium high heat. Working in batches of two add the beef and sear it until browned. Set aside on a plate

Add the celery, carrots, onion and garlic and saute, scraping the bottom of the pot with a wooden spoon to loosen any browned bits from the pot. Cook for 5 minutes until the vegetables have softened

Add the tomato paste and stir, cook for 1 minute before adding in the red wine, beef stock, dried thyme and bay leaves. Stir. Return the pieces of beef to the pot and bring to a gentle simmer. Cover the pot with a lid and transfer to the oven to cook for 2 hours (or until the meat is fall apart tender and can easily be shredded with 2 forks).

Once the beef is tender, remove the beef pieces from the pot and set aside on a plate.

Pour all of the sauce from the pot through a sieve into a bowl. Use a spoon to push firmly down on the bits of vegetables in the sieve to get as much liquid out as possible. Discard the “pulp” left in the sieve.

Return the sauce to the pot and place on the stove on high heat. Leave the sauce to boil for approximately 5 minutes until it has thickened and begun to reduce. Taste and continue to boil further if you prefer a stronger flavor. You should be left with approximately 2 cups of sauce.

Serve the pieces of beef over mashed potatoes with the sauce spooned overtop.