Preheat the oven to 200°C.
Brown the beef chunks in oil in a large saucepan over high heat in batches.
Remove the browned beef and set aside on a plate.
Fry the chopped onions, celery, and carrots in the same pan for 5 minutes.
Season the vegetables with salt and pepper.
Combine the beef and vegetables in a large ovenproof dish.
Pour the beef stock over the meat and vegetable mixture.
Arrange a layer of 0.5cm thick potato slices over the top.
Dot the potatoes with butter and cover the dish tightly with foil.
Bake for 1 hour, then remove the foil and bake for 15 minutes more.