1. Ensure that the Fish chunks are thoroughly washed before applying a small amount of Salt and Turmeric Powder to them.
2. In a large bowl (preferably a Glass Bowl with a lid), whisk the plain curd or plain yogurt using a spoon.
3. Next, incorporate the Onion Paste, Ginger Paste, Garlic Paste, Bengali Garam Masala Powder, Kashmiri Chilli Powder, Turmeric Powder, Sugar, Salt, and Mustard Oil into the yogurt, ensuring they are well combined.
4. To dilute the mixture, add a minimum of two cups of water.
5. Place the Fish pieces onto the yogurt mixture, ensuring that each piece is evenly coated, and allow them to marinate for approximately 45 minutes to 1 Hour.

To Make Doi Maach in Microwave:

1. Place the fish, along with the marinade, into a microwave-safe bowl that has a lid.
2. Microwave the bowl on medium heat, or 40%, for 20 minutes.
3. Following this, uncover the bowl and insert sliced green chilies.
4. Proceed to microwave the bowl on high heat, or 100%, for an additional 10 minutes. This will infuse the Doi Maach with a delightful scent of green chilies while preserving their vibrant color.

Making Doi Maach in normal Stove:

1. If a microwave oven is not accessible, simply place the fish in a pan with the curd mixture and cook over low heat for 15 minutes.
2. Then, increase the flame to high and cook for an additional 5 minutes after adding green chilies.
3. Allow the dish to rest for 10 minutes before serving.