Traditional Bengali Curries

Like many coastal cuisines, fish and coconuts are extensively used in Bengali cuisine. Fish is so much a part of the daily diet that it even forms a part of the traditionally vegetarian Brahmin diet. Unlike North Indian cuisine, parboiled rice is a staple. The flood prone land does not support a large dairy industry and so dairy products like ghee, milk or yogurt are not extensively used in daily cooking. A typical Bengali meal consists of Rice, Dal, Vegetables and Fish. This apparent simplicity hides the fact that over 18 different types of cooking techniques are called upon to produce an array of delicious curries.
The curry base : See Column 1
Mustard paste, khus khus paste, pulses, vegetables, yogurt, onion- tomato are all used as curry bases across the state. A selection of popular curries is listed below:

The Bengali Raita is very similar to a regular North Indian raita, and uses most salad vegetables. As mentioned above, yogurt is still not a part of the daily diet in Bengali homes. But raita is gaining popularity and will very likely be regarded as a Traditional Bengali curry a few decades down the line.
The Posto is a unique Bengali curry built on khus khus paste.
Shorse Jhol is another unique curry made from a paste of mustard seeds.
Shukto is a combination of the Posto and Shorse Jhol as it is made from mustard seeds and khus khus, both blended together. It usually has a mix of vegetables, with atleast one bitter vegetable.
Rezala is Mogul curry made by simmering a wide variety of goodies in flavoured yogurt. It has to be cooked on low heat with constant stirring to prevent the yogurt from splitting.
Dalna can be dry or have a stew like consistency and is made from onions, tomato and coconuts. Dhokkar ( refried chana dal patties) is commonly used in a Dalna.
Shak is a dry spinach curry. It can be made from any leafy vegetable.
A variety of dals like Masoor dal, Mung dal and Chana dal are cooked across the state.
Ambal is one of the very few Bengali dishes which use tamarind.

Flavouring : See column 2
The usual North Indian flaourings of cumin, garam masala, turmeric, coriander, fenugreek, ginger, chili, kalonji, are all used in Bengali cuisine. Cinnamon , cloves, cardamom are occasionally used. A mixture of five spices, the Panch Phoran is widely used. Unlike North Indian curries, mustard oil is extensively used. Coconut oil / sesame oil / Asafetida / curry leaves are almost never used. Traditionally, a curry base is often paired with a particular flavouring. For example, a Rezala (Column 1 , row 4) is usually flavoured by bay leaves, cardamom and cloves ( Column 2, row 3). This is because a Rezala is a Mogul curry and so uses typical Mogul flavourings. However, it is not a crime to flavor a Rezala with Panch Phoran. Similarly feel free to experiment with various flavouring options listed in column 2.

Goodies : See Column 3
Traditional curries use select pairings of a curry base and goodies. For example, dals are usually paired with Dhokkar. Similarly, a shukto always has bittergourd, eggplant and plantain. But feel free to use your favourite goodies in the curries above. They might not be traditional, but they’ll very likely be delicious. Though listed here, mushroom and paneer are not frequently used in Bengali curries. However, a wide variety of veggies and leafy greens are used. Dhokkar is commonly used as a vegetable substitute. (Dhokkar : Boil Chana dal. Mash and pat into a sheet. Cut into diamond shapes. Shallow fry in oil. Add to simmering curry).

What makes a curry a Bengali Curry ?
1. Use of mustard oil
2. Use of mustard paste & khus khus paste as curry bases.
3. Use of panch phoran for flavouring
4. The use of fried chana dal patties (Dhokkar) as a vegetable substitute.
5. Use of sugar in curries and
6. The huge array of cooking techniques.

And that's my entry for Sandeepa's Regional Cuisines of India.