1. Melt the butter in a saucepan.
2. Fry the onion paste to a transparent stage.
3. Add the garlic paste and the beans.
4. Fry briefly and add the tomato puree and lemon juice.
5. Add the water and season well with the pepper and salt.
6. Simmer, covered, till the beans are cooked.
7. Serve hot, topped with the parsley.