In a large pot or Dutch oven, 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 pot, add the chopped onion and garlic. Sauté until the onion is translucent, about 3-4 minutes.

Return the beef to the pot. Add the beef broth, carrots, potatoes, celery, thyme, rosemary, bay leaves, salt, pepper, tomato paste, and Worcestershire sauce. Stir well to combine.

Bring the mixture to a boil, then reduce the heat to low. Cover and simmer for 1.5 to 2 hours, or until the beef is tender. Stir occasionally.

If using, mix the cornstarch with a little water to create a slurry. After the stew has simmered, stir in the slurry to thicken the stew. Add the frozen peas if desired and cook for an additional 5 minutes.

Remove the bay leaves before serving. Adjust seasoning if necessary. Serve hot with crusty bread or over rice.