Preheat the oven to 160°C. Heat 1 tablespoon of olive oil in a large oven proof saucepan. Add the beef and brown all sides (6-8 minutes).
Remove the beef from the saucepan and set aside. Add remaining olive oil and add the onions, carrots, celery, spring onion and potatoes. Add the bay leaves, oregano, garlic, juice, boiling water and vegetable bouillon. Bring to a boil and return beef to the saucepan. Spoon over the sauce, cover and cook in the oven for about 1,5 to 2 hours until the meat has cooked completely.
Remove from the oven and transfer everything except the sauce to a large dish. Thicken the gravy by placing the saucepan on medium heat and adding the flour. Whisk for a few minutes until the sauce has reduced and thickened. Add the butter and mix until melted. Transfer the gravy to a small bowl and serve with the roast.