Pat the beef dry with paper towels and season all of the beef evenly with salt and pepper on all sides. Then dridge the beef in flour, shaking off any excess flour so that there is a light and even coating.
In a wide Dutch oven, drizzle olive oil and bring up to medium heat. Add the bacon and cook until the bacon has rendered it's fat, for about 8-10 minutes. Then remove with a slotted spoon, leaving the bacon fat in the Dutch oven.
In the same Dutch oven, sear the beef cubes on all sides until deeply charred. Depending how wide your Dutch oven is, you'll be searing in batches. Once done, set aside to a plate.
Add the chopped onion, carrots and celery and saute for 5-7 minutes until the vegetables begin to soften. Then add the chopped garlic and fresh oregano and continue sauteing for another minute.
Pour the red wine in and use a sturdy spoon to scrape up any meaty bits from the bottom of the Dutch oven and let the wine reduce by half. Add the tomato paste and stir through for another minute.
Next, add the seared beef back in, with any accumulated juices, as well as the potatoes, mushrooms, bacon and bay leaves. Pour in the beef stock and bring the beef stew to a boil, then reduce down to a simmer.
Place the lid onto th4e Dutch oven, leaving a small opening and cook for 3 hours, or until the meat and potatoes are tender.
Once done, remove the bay leaves and discard and teaste for seasoning. Ladle the beef stew into wide bowls and garnish with additional fresh oregano and serve.