To begin making the Vazhaithandu Lemon Rasam Recipe, whisk the yogurt salt and water in a bowl. 

Peel the outer skin of plantain stem/Vazhaithandu and discard it.  Place the cut banana stem in the yogurt. This prevents it from getting discoloured.

Preheat the pressure cooker over medium heat; once heated, add the mustard seeds, cumin seeds and allow it to crackle. Add the ginger, garlic, asafoetida, curry leaves and stir for a few seconds.

Finally add the banana stem along with the yogurt water, the tomatoes and all the powders - coriander, cumin, turmeric, red chilli and salt.

Stir, cover the pressure cooker & cook for about 3 whistles and turn off the heat.

Release the pressure immediately, either by lifting the weight with a fork or by placing the cooker under cold water.

Once done, open the cooker and stir in the cooker dal and squeeze in the lemon juice. Add a little water and salt and chilli if required according to your taste. 

Bring the Vazhaithandu Lemon Rasam Recipe to a brisk boil and allow it to froth up - this will take about 4 to 5 minutes. 

Once done, turn off the heat and stir in the chopped coriander leaves and stir.

Serve the Vazhaithandu Lemon Rasam along with a bowl of steamed rice and a Andhra Style Beetroot Vepudu Recipe (Stir Fried Beetroot) for a lunch or a quick and wholesome weeknight dinner.