Begin by heating the vegetable oil in a large pot over medium-high heat until shimmering.

Season the beef chuck roast with salt and black pepper, then carefully place it in the pot. Sear until browned on all sides.

Remove the beef from the pot and set it aside on a plate.

In the same pot, add chopped onion, carrots, and celery. Cook until softened, about 5 minutes.

Pour in the red wine (or additional beef broth), beef broth, Worcestershire sauce, rosemary, parsley, and extra black pepper. Stir well.

Place the seared beef back into the pot, ensuring it's covered by the liquid. Bring to a boil.

Reduce the heat to low, cover the pot, and let it simmer for 2 hours.

In a small bowl, mix cornstarch with cold water until completely dissolved. Stir this mixture into the stew.

Add the medium potatoes, cut into chunks, and cook for an additional 30 minutes, or until the potatoes are tender.