Rinse the whole moong and soak in plenty of water for 4-5 hours or overnight.

Drain well and grind with the ginger, green chili, salt and a little water to a smooth, pourable batter.

Heat a dosa tawa and pour a ladle of batter, spreading it into a thin circle.

Drizzle a little oil around the edges and cook until the base is golden and crisp, then fold. Repeat with the remaining batter.

Rinse the arhar dal and pressure cook with turmeric and enough water until soft. Mash well and set aside.

Peel and cube the ash gourd. Soak the tamarind in warm water and extract the pulp.

Heat the oil in a pan. Add the mustard seeds; once they splutter, add the urad dal, chana dal and curry leaves.

Add the onion, garlic and ginger and sauté until the onion softens.

Add the tomato and cook until it breaks down, then stir in the coriander powder, red chili powder, sambar masala and asafoetida.

Add the ash gourd cubes, tamarind extract, salt and enough water. Cover and simmer until the ash gourd is tender.

Stir in the mashed dal and simmer for a few minutes, adjusting the consistency with water. Finish with the tempering of oil, mustard seeds and curry leaves.

Grind the dry coconut with the green chili and salt to a coarse paste, adding a little water as needed.

Heat the oil in a small pan, add the mustard seeds, urad dal and chana dal and let them splutter.

Pour the tempering over the chutney and mix well.

Serve the dosas hot with the ash gourd sambar and coconut chutney.