Drain the Banana blossom and discard the brine. Transfer to a bowl.
Add the turmeric, kala namak, wakame and the juice of one lemon.
Coat each piece of banana blossom in the marinade and set aside for 30 minutes.
Once the marination time is complete, remove the banana blossom from the marination and coat each blossom in potato starch. Cover them thoroughly and gently shake off the excess potato starch.
Mustard Sauce
Soak the mustard seeds in water, either overnight or for a minimum of two hours.
Drain the water from the mustard seeds and add to a blender along with the green chillies and 100 ml of water and blend into a smooth paste.
Set aside the mustard-chilli paste.
Final cooking
Heat the mustard oil in a pan and allow it to smoke. Once it reaches smoking point, take off the heat and allow it to cool. You will see the oil has changed colour from an orangish yellow to a pale yellow colour.
Once the oil has cooled, put the pan on a medium heat and pan fry each coated banana blossom. Turn to fry each side until golden to light brown.
Once all the blossoms are pan fried, transfer to another plate. Retain the oil in the pan.
In the same pan and oil, over medium heat, add the mustard-chilli paste and 300 ml of water and briefly let the sauce simmer for a minute or two.
Season the sauce with kala namak and add the turmeric powder. Add the pan fried pieces of the banana blossoms and simmer for five minutes, stirring to coat the blossoms in the sauce.