Heat the oil in a flameproof casserole, add the beef, in 3 batches, and cook over a high heat for 5 minutes until browned all over. Remove from the pan with a slotted spoon.
Add the onions and red peppers to the pan and cook gently for 10 minutes until softened. Stir in the paprika, marjoram and caraway seeds and cook, stirring, for a further 1 minute.
Return the beef to the pan, add the stock, tomato purée and salt and pepper to taste and bring to the boil, stirring. Reduce the heat, cover and simmer gently for 1½–2 hours. You can remove the lid for the final 30 minutes if the sauce needs thickening.