Add the olive oil to a heavy soup pot set over medium-high heat. Season the beef with salt and pepper, then cook until well-browned on each side – about 10 minutes. Transfer to a cutting board and cut into 1/2-inch to 1-inch cubes.
Lower the heat to medium and add the carrots, celery, onion, peppers, and garlic; cook until soft – about 8 minutes. Stir in the paprika.
Add the chicken stock and bay leaves. Return the beef to the pot. Bring to a simmer and let cook 2 hours, or until the meat is tender.
Add the potatoes and cook another 30 minutes, or until soft.
Remove from heat and stir in the vinegar. Season to taste with salt and pepper. Top with parsley, if desired.