Heat 2 cups water in a deep non stick pan.
Cut drumstick into 1 inch pieces and add to the pan.
Cube potato and red pumpkin and add along with salt.
Cover and cook till vegetables are cooked. Pressure cook dal with salt, turmeric powder and 1 cup water till 3-4 whistles are given out.
Open the lid of the cooker when the pressure reduces completely and mash the dal well. Heat oil in a deep non stick pan.
Slice sambhar Add asafoetida, mustard seeds, curry leaves and sambhar onions to the oil in the pan and sauté. Add green chillies and continue to sauté till fragrant.
Add red chilli and sambhar masala and mix and sauté for 1 minute.
Add a little water and mix. Add dal and cook, stirring, for 3-4 minutes.
Add the vegetables along with the water in which they were cooked and mix.
Add tamarind pulp and mix well. Adjust consistency by adding water as required.
Simmer for 4-5 minutes. Serve hot with hot idli or dosa.