First, temper the whole spices. In a large non-stick frying pan, heat the oil over medium flame. Once the oil is hot, add mustard to the pan and allow it to pop. Next, add the cumin seeds and let them crackle. Now, add the curry leaves to the pan — be careful, they spit — along with chopped green chillis and hing.
Fry the matki usal base. Add the chopped onions to the pan and gently fry until they soften slightly. Add the ginger garlic paste and cook until aromatic (30 seconds or so), before adding the chopped tomatoes and salt. Let the base cook down until the tomatoes are soft, then add the dried spices; turmeric, coriander, and red chilli powder. Stir well.
Add the sprouted moth beans and mix everything. Let the mixture cook for a few minutes, adding a splash of water if necessary*.
Finish the matki usal with goda masala, freshly chopped coriander, and lemon juice. Mix everything and turn off the heat, before serving hot (or cold) with mixture/farsan of your choice.
Notes
* The texture of matki usal should be dry/semi-dry, so try to not add too much water unless necessary.