Heat 2 tablespoon of butter in a large deep pan.
Add chopped green chillies, garlic , ginger and shallots. Sauté for 2-3 minutes on medium heat until raw smell of shallots vanishes.
Now add finely chopped banana stem , pinch of turmeric powder and saute for a minute.
Add 3 cups of water or stock , salt to taste .
Cover lid and cook for good 12 to 15 minutes on medium high heat. As banana stem is rich in fibres, it takes more time to get cooked. Alternatively, you can pressure cook for 1 to 2 whistles.
Once banana stem is cooked well, it will be soft . ( At this stage , if you wish you can strain water, set aside and blend the cooked banana stem in a blender to extract juice.)
Now make slurry from 1 tablespoon cornflour and 2 tablespoon of water , mix it along with cooked banana stem .
Stir well and bring to a gentle boil until it starts to thicken.
Now add cumin powder, fennel seeds powder, black pepper powder, coriander leaves and stir well.
Turn off the stove , squeeze fresh lime juice to taste.
Top with cornflakes and serve hot.