First, soak the urad dal and moong dal for 2 hours. Once the dal is soaked, rinse well, remove the skins, and drain all the water. In a blender, grind the urad dal, moong dal, green chilies, and ginger into a fine paste.

Add salt to the ground dal and beat it well until the batter becomes light and fluffy. Heat oil in a deep pan, shape the batter into small or large vadas, and fry them on medium heat until golden brown. Prepare all the vadas in the same way.

For the sambar, wash the toor dal and cook it in a pressure cooker with salt, turmeric, and all the chopped vegetables, adding 4 cups of water. Cook for 3-4 whistles. Release the pressure and whisk the dal. In a pan, heat oil and add dried red chilies, asafoetida, and mustard seeds for tempering. Then add curry leaves and onion and sauté.

Add tomatoes, red chili powder, sambar masala, and tamarind pulp. Add 1/2 cup water and cook, then add the cooked dal mixture and simmer until it boils. Finally, add jaggery. Your tangy, sweet, and spicy sambar is ready.

Serve the hot sambar with vadas. When serving, sprinkle finely chopped onion on top of the sambar vada and enjoy it hot.