Heat the oil in a large pot or Dutch oven over medium-high heat. Sear the cubed beef until browned on the outside. Remove the beef from the pot and set aside.
Sauté the onion and carrots in the same pot until the onion starts to soften.
Stir the minced garlic into the onion and carrots and cook for about 30 seconds, until fragrant. Season the vegetables with the Greek seasoning and black pepper.
Spoon the tomato paste over the vegetables and mix until combined. Cook the tomato paste for about 1 minute.
Place the diced tomatoes and seared beef in the pot.
Deglaze the pot with the water or beef broth, scraping up any browned bits from the bottom.
Bring the stew to a boil, then reduce the heat to a simme until the carrots are tender.
Taste the stew and season with salt as needed. Serve.
Notes
If using all-purpose Greek seasoning, wait to add salt since many blends already contain it. Taste the stew near the end of cooking and add salt as needed.