Make a paste of onion, ginger, garlic and chillies. Keep it aside. Make the paste of all the ingredients listed for curry paste with 1/2 cup of water. Keep it aside.
Heat oil and add all the whole spices listed for the curry and let them splutter. Add in the onion paste and fry for 7-8 minutes. Add in some salt so the onions cook faster.
Whilst the onions are cooking, parboil the long beans, baby corn separately.
Once the onion is cooked, add in the coconut paste and cook further 5-6 minutes.
Once the coconut paste is cooked, you will see the oil releasing from the sides. Add in the turmeric, red chilli powder and mix well. Saute for another 2 minutes.
Add in all the vegetables and 1 cup of water. Simmer for 5 minutes. Adjust salt.
Garnish with coriander and serve with Idiyappam or dosas.