In a large skillet, heat the olive oil over medium-high heat. Add the beef cubes and brown them on all sides, about 5-7 minutes. Remove the beef and set aside.
In the same skillet, add the diced onion and minced garlic. Sauté for 3-4 minutes until the onion is translucent.
In a slow cooker, combine the browned beef, sautéed onion and garlic, sliced carrots, diced potatoes, chopped red bell pepper, diced tomatoes, beef broth, Worcestershire sauce, thyme, oregano, salt, and pepper.
Stir everything together until well mixed. Cover and cook on low for 7-8 hours or on high for 4-5 hours, until the beef is tender and the vegetables are cooked through.
Once cooked, taste and adjust seasoning if necessary. Serve hot, garnished with fresh parsley.