In a pan, dry fry all the ingredients over medium heat until fragrant or one shade darker in colour. Care should be taken not to burn the spices. Transfer to a bowl immediately and let it be cooled completely at room temperature. 

Make a powder of the spices by using a mortar-pestle. 

If you want to use a food processor/mixer grinder to make the spice powder, then double the ingredients and proceed further. You can store the rest of the masala in an airtight container for future use.

Peel the potatoes and cut into halves, keep aside.

Peel and grate the onion, or you can use a paste of the onion too.

Heat oil in a deep frying pan, add the potatoes and sauté over medium heat until they turn golden in colour. Remove from the heat and keep aside.

In the rest of the oil temper with bay leaf and cumin seeds.

Add the grated onion and cook over medium heat until brown in colour. 

Next, add the ginger-garlic paste, mix and fry for a few seconds. 

Add the dum aloo masala, turmeric powder, salt and green chilies, mix well. Now add a few tablespoons of water, and keep stirring the masala until it starts leaving oil. Adding water at this stage prevents the spices from burning, helps to dissolve the masala, and enhances the flavour.

Next, add the potatoes, mix well with the masala and cook for 2-3 minutes over medium heat, keep stirring in-between. 

Add 1 cup of warm water, mix and cook over low heat with the lid on until the raw smell of masala goes and the potatoes are cooked through. Keep stirring in-between to prevent from burning or sticking to the bottom of the pan.

The gravy of this Aloor Dom would be on the thicker side, so adjust the amount of water to make the gravy accordingly.

Add sugar, chopped coriander leaves, and garam masala powder towards the end of the cooking, mix well and cook uncovered for 2-3 minutes. 

Turn off the heat, and transfer the Kosha Aloor Dom to a bowl.

Serve this delicious Aloor Dom hot with Luchi, Peas Kochuri, Hinger Kochuri, etc.