Dry and flour beef:
Thoroughly dry the beef cubes using paper towels, then coat them evenly with the flour.Sear beef cubes:
In a large skillet over medium-high heat, warm the olive oil. Arrange the beef in one layer and sear each side for 2-3 minutes until a deep brown crust develops. Move the seared beef to the slow cooker.Deglaze skillet:
Add a small amount of beef broth to the hot skillet and deglaze by scraping up the browned bits. Pour this liquid over the beef in the slow cooker.Layer vegetables:
Place the cubed potatoes, thick carrot rounds, diced onion, and minced garlic on top of the beef in layers.Whisk broth mixture:
In a separate bowl, combine the remaining beef broth, tomato paste, Worcestershire sauce, salt, and pepper. Whisk until smooth, then pour over the vegetables and beef.Slow cook beef:
Put the lid on the slow cooker and cook on LOW for 7-8 hours or on HIGH for 4 hours, until the beef is fork-tender.Thicken with slurry:
About 30 minutes before serving, mix the cornstarch with cold water to create a smooth slurry. Stir this into the slow cooker along with the frozen peas.Add peas and parsley:
Replace the lid and cook for another 30 minutes until the gravy thickens, turns dark brown, and coats a spoon. Sprinkle with fresh parsley before serving.