Cut saragva into medium-sized pieces and keep it aside.
In a pan, add oil, mustard seeds, cumin seeds, ajwain, hing, and curry leaves. Sauté it.
Add drumstick pieces and salt. Stir-fry the drumstick on medium-high flame for 2 minutes.
Cover the lid and cook the drumstick on low flame till it slightly changes its color and becomes soft.
Meanwhile, in a pan, add besan and sauté till it slightly changes its color. Add the roasted besan into a bowl, also add a pinch of salt, red chilli powder, coriander powder, and ½ cup water. Mix well and make a slurry. Keep it aside.
Then add ginger-garlic paste and sauté it.
Add turmeric powder, red chilli powder, coriander powder, sugar, and slightly hot water. Sauté the masala till it releases oil from its sides.
Add ¾ cup water and bring it to boil.
When the mixture starts boiling, add the besan mixture and mix well.
Cover and cook for 5 minutes on low flame till oil releases from sides.
Add some lemon juice and coriander leaves. Mix well.
Serve Saragva Nu Shak with roti and dal.