Chop onion; cut green peppers, tomatoes, broccoli, and cauliflower into 3 cm cubes. Melt butter and saute� onion. Add all the remaining vegetables and stir-fry for about 5 minutes over medium heat. Add the spices and vinegar. Stir in the tomato puree, and simmer for about 5 minutes. Season to taste with salt and fresh ground pepper.