boil dal till it is cooked well

.
In a sauce-pan, heat 2 tsp oil and add red chilli  to it the mustard seeds,and the cumin seeds. hing
When  the mustard seeds begin to splutter add garlic onion and the curry leaves, tomatoes and green chilly.

add cucumber
Cover and let it cook well till the tomatoes and cucumber are soft .
Add the cooked dal and mix well. add butter
Remove from fire and garnish with chopped fresh coriander leaves.