Heat the olive oil in a large pot or Dutch oven over medium heat. Add the onion and cook, stirring occasionally, until the onion becomes translucent but does not get any color, about 10 minutes. Increase the heat to medium-high, add the bell pepper, celery, garlic, a generous pinch of salt and a few grinds of pepper and cook, stirring occasionally, until tender, about 10 minutes.
Add the beef, a generous pinch of salt and a few grinds of pepper to the pot and cook, stirring to break the meat into small bits, until browned, about 10 minutes. Stir in the tomato paste and oregano and cook, stirring, for 3 minutes.
Add the Worcestershire sauce, tomatoes with their juices, sugar and bay leaf. Bring to a boil, reduce to a simmer and cook, stirring occasionally, until thickened, about 45 minutes.
Copyright 2013 Television Food Network, G.P. All rights reserved