Okra with tomatoe & olive Oil (Greek recipe)

Ingredients450g (1lb) Fresh Okra
3 oz butter
1/4 cup vinegar or lemon juice
1 medium Oninon, finely chopped
1 tomatoe pureed
1 tablespoon tomato paste
Salt & pepper

Wash okra and cut off stem ends without cutting into the flesh. Place okra in bowl, sprinkle with vinegar or lemon and set aside for 1/2 hour
Melt butter in casserol and saute the onions on a low heat until limp and transparent.
Add the Okra and cook until it turns to a nice dark green and sftens up a little.
Add the tomatoe paste and tomatoe puree salt & pepper and a little water to cover the food.Cook until the okra is soft and starts opening up on the sides. Serve on the side of some meat.