Barbecue Butter Beans

1 tablespoon polyunsaturated vegetable oil
1 onion, peeled and chopped
1 clove garlic, peeled and crushed
2 tomatoes, skinned
pinch of sugar
pinch of dry mustard
pinch of chilli powder
1 tablespoon tomato puree
1 x 275 g/10 oz can butter beans, drained

Heat the oil in a saucepan, add the onion and garlic and cook until softened. Add the remaining ingredients, except the beans, and simmer for 10 minutes. Stir in the beans and heat thoroughly. SERVES 4