Take baby corn in a sauce pan, cover with water and boil for 5 mins till it is cooked, drain and take it in a bowl. Now add in cornflour, salt and pepper and mix well. Add little water as needed. Mix well.
Now heat little oil in a pan, add the babycorn in it and fry till golden brown and crispy. Drain and set aisde.
In the same oil, add ginger garlic and fry till golden.
Add in onion, green chillies, salt and cook till golden brown.
Now add in ketchup, soy sauce, chilli powder and mix well.
Add water and bring it to a boil. Add vinegar, sugar and mix well. Now add in some of the cornflour water and mix well. Once it thickens, add baby corn back in.