Wash and soak brown lentils for 30 minutes in warm water. Then drain the water.
In a large pot take soaked lentils, all the ingredients for brown lentils, and 3 cups of water. Bring the lentil to boil. Then reduce heat to medium-low and cover the pot. Cook for 20-30 minutes until lentils are soft.
Add tamarind pulp and give it is a good stirring to dissolve onion and tomatoes. Add water if needed to adjust consistency.
Tempering:
Heat oil in a pan and fry garlic until lightly golden. Add cumin and curry leaves and fry for another few seconds. Pour the tempering over the lentils. Lentil are ready to serve. Garnish with fresh coriander and serve hot.