Heat the oil in a large pot over medium heat. Add the beef cubes and cook, turning, until completely browned, about 10 minutes.
Remove the meat from the pot and pour off any excess oil.
Add the onion and tomato paste to the pot. Cook, stirring frequently, until the onion is tender, 5 minutes. Return the meat to the pot along with the broth, mixing them with the onion and tomato paste.
Reduce the heat to low and cover the pot. Let the mixture cook slowly for 1 hour to 1 hour and 30 minutes, or until the meat is tender.
Uncover and stir in the potatoes, carrots, rosemary, thyme, bay leaf and cayenne pepper. Recover, and simmer for another 45 minutes. Add a little water, as needed, if the stew seems too thick.
Remove the bay leaf and sprig of rosemary. Taste and season with salt, as needed.