In a cooker, boil the colacacia for 1 whistle. Peel the skin, and if the pieces are too big, cut it into 2 halves or any suitable size.
Heat 2 tsp oil in a kadai. Add 1/2 tsp Turmeric powder and 1/2 tsp red chilly powder.
Add the boiled colacacia and mix well.
Add salt and cook till the spices coat the pieces well and colacacia becomes little crisp.
Transfer these to a different vessel and keep it aside.
In the same kadai, heat 2 tsp oil and add cumin seeds.
Once it splutters add onions.
Add green chilly and ginger, and saute till the onions turn translucent.
Add 1 tsp red chilly powder, 1 tsp coriander powder, little salt and 1/2 tsp turmeric powder. Cook well for 2 to 3 minutes.
Add 1/4 cup water and let it boil for 2 minutes.
Add the chopped tomatoes and little more salt. Mix well and cook till tomatoes turn mushy and oil releases from the sides.
Add curd and mix well.
Add 1/2 cup of water again and boil till the gravy slightly thickens and oil separates.
Add the roasted colacacia. Mix well and cook for 2 minutes.
Add kasoori methi. Mix well and cook for 2 minutes.
Switch off the stove. Garnish with coriander leaves. Your Dum Arbi is ready