Hungarian Goulash

1lb lean stewing steak
2 tablespoons oil
15oz can tomatoes
2 onions, chopped
1 tablespoon tomato puree
2 tablespoons paprika
1lb potatoes
1/2 teaspoon caraway seeds
1 teaspoon cornflour
salt & pepper to season
sour cream
Dice meat into cubes and brown in the oil. Add onions, tomatoes, tomato puree and paprika. Cook gently for an hour or so. Add potatoes, caraway seeds and season to taste. Cook until potatoes are done. Mix cornflour with a little water and add to goulash. Cook until sauce thickens. Top each serving with sour cream.