1. Boil dal till it is cooked well.
2. In a sauce-pan, heat 2 tsp oil and add dry red chillies, mustard seeds, cumin seeds, hing / asafoetida.
3. When the mustard seeds begin to splutter, add garlic, onion, curry leaves, tomatoes, green chillies, cucumber.
4. Cover and let it cook well till the tomatoes and cucumber are soft.
5. Add the cooked dal and mix well. also add butter.
6. Remove from fire and garnish with chopped fresh coriander leaves.