Dry roast the corn kernels in a non-stick pan for five to six minutes.Heat butter in a deep non-stick pan, add garlic and onions and sauté for three to four minutes or till they turn soft.
Add the roasted corn kernels and saute for three to four minutes. Add the vegetable stock, capsicums and salt and bring the mixture to a boil. Cover and cook for five minutes.
Take the pan off the heat and allow the contents to cool. Blend it coarsely with a hand blender. Add lemon juice, stir and bring the soup to a boil. Serve hot garnished with coriander leaves.