Preheat the oven to 160°C and heat olive oil in a flameproof casserole dish.
Brown the beef in batches, remove with a slotted spoon, and set aside.
Fry the chorizo and onion until softened and fat is released.
Add carrots and parsnips, cook until slightly softened, then stir in flour for 3 minutes.
Pour in the wine while stirring, bring to a boil, then add the beef stock.
Return beef to the pan, season, cover, and braise in the oven for two hours.
Mix self-raising flour, salt, suet, rosemary, and water into a soft dough.
Divide the dough into eight oval dumplings and place on a lined baking tray.
Bake dumplings on the top oven shelf during the last 25 minutes of the beef cooking time.
Boil potatoes for 15 minutes, drain, and pass through a ricer.
Mix potatoes with horseradish, butter, cream, and seasoning.
Serve the mashed potatoes topped with the beef stew and dumplings.