Brown the Meat:
Begin by heating the olive oil in a large skillet over medium-high heat. Toss the beef cubes with the flour, then brown them in batches. Take care not to overcrowd the pan, as this prevents proper searing, allowing the meat to lock in its natural juices and develop rich flavor.
Combine Stew Ingredients:
Once the beef is browned, transfer it to a 7+ quart crockpot. Add the diced tomatoes, beef broth, tomato paste, carrots, celery, peas, onion, garlic, thyme, rosemary, bay leaves, salt, and pepper. Stir gently to combine. Cover the crockpot with the lid and set the temperature to high for 4 to 6 hours, or low for 8 hours. For a more tender result, opt for the longer, slower cooking time.
Prepare the Dumplings:
While the stew is cooking, mash the cooked potatoes. In a separate bowl, combine the mashed potatoes with flour, baking powder, egg, Parmesan cheese, oil, garlic powder, thyme, and salt. Mix until the ingredients are just incorporated. If necessary, add a small amount of water to form a dough that can be shaped into golf ball-sized dumplings. Use a medium-sized cookie scoop for uniformity. Refrigerate the dumplings until ready to add them to the stew.
Finish the Stew:
One hour before serving, whisk together the cornstarch and water, then stir the mixture into the stew to thicken the broth. Gently add the dumplings, pressing them slightly into the liquid to ensure they do not stick together. Continue cooking for another hour, allowing the dumplings to steam and soak up the flavors of the stew.
Serve and Garnish:
When ready to serve, sprinkle fresh parsley over the stew for a pop of color and freshness. Serve hot and enjoy!