Boil the sweet corn till they are cooked. Drain and keep aside.
Take a mixing bowl and mix the sweet corn, chopped onion and a pinch of salt.
Cut the thick edges of the bread slices. (This step is optional)
Apply butter on one slice of bread.
Now spread 1 tablespoon sweet corn and onion mixture on the slice of bread. Add more mixture if desired or if any part of the bread looks empty.
On top of this spread 1 tablespoon grated cheese.
Close this with another bread slice making a sandwich.
Grill it in a toaster or a Panini grill press.