In a pan/kadhai heat the oil. Add mustard seeds and cumin seeds and allow them to sputter. Now add in the urad/chana dal and asafoetida and fry for about a minute. Tip in the curry leaves and cook for a minute.
Add in the onion and fry lightly till it is transparent. Add the tomato in now along with the slit green chillies and turmeric powder and fry for about a couple of minutes.
Now add about 3 cups of water and let it come to a boil. Add the roasted vermicelli, boiled vegetables and salt. Mushroom does not need to be boiled.
Mix and cover with a lid. Cook on low heat till the water is absorbed and the vermicelli is cooked well.
Takes about 10 minutes. Take it off the heat. Taste and adjust salt. Sprinkle lemon juice and garnish with coriander. Serve hot.
You can use roasted vermicelli from MTR. It reduces the cooking time further.You can use any vegetables you like but make sure that they are boiled unless they cook very quickly.Tastes good even at room temperature.