01 - Heat vegetable oil in a large Dutch oven or heavy-bottomed pot over medium-high heat. Brown beef cubes in batches, setting aside as they brown.
02 - Add onion to the pot and sauté for 3 minutes until translucent. Stir in garlic and cook for 1 minute more.
03 - Return browned beef to the pot. Add carrots, parsnips, and potatoes. Stir in tomato paste and cook for 2 minutes.
04 - Pour in beef stock and Guinness. Add Worcestershire sauce, bay leaves, thyme, salt, and black pepper. Bring to a boil, then reduce heat to low, cover, and simmer for 1½ hours, stirring occasionally.
05 - Whisk together flour, baking powder, and salt in a bowl. Rub in cold butter with fingertips until mixture resembles coarse crumbs. Stir in milk and parsley, mixing just until combined.
06 - Remove lid from stew after 1½ hours. Drop tablespoonfuls of dumpling dough onto surface of simmering stew (about 12 dumplings).
07 - Cover and cook for 25 minutes, or until dumplings are puffed and cooked through.
08 - Discard bay leaves, adjust seasoning if needed, and sprinkle with chopped parsley before serving.