In a sauce pan, add corn, peas, salt and water (around 3/4 - 1 cup) and cook on a low flame for 5 minutes or until the veggies are cooked.
I have used frozen corn/peas and it normally doesn`t take much time to cook.
Drain water. (If you are using dried green peas, then you must soak overnight, pressure cook for couple of whistles.
I would recommend fresh ones over dried peas.)
Meanwhile, add 1 tsp of oil in a small pan.
When it is hot add finely chopped onions and saute until it is golden brown. This will take 3-4 minutes on a medium flame.
Add corn, peas and saute for 2-3 minutes.
It is ok if the veggies are a little moist.
It will help the spices to blend well.
Now add pepper powder, amchur powder, chaat powder and mix it well.
Add a little more salt if necessary, keep stirring so that it doesn`t stick to the pan.
Turn off the gas and let it cool for a while.
Turn the spatula upside down and mash the peas and corn.
You can also use potato masher if you have one.
This will help the masala to stick to the bread.
Add finely chopped cilantro leaves and mix it.
Divide the masala into equal parts.
Take 2 slices of bread.
Add the masala on one bread, spread it and close it with the other slice.
Repeat the same for other slices.
Place them carefully on a sandwich maker and cook until the light goes off (Please refer to the cooking instructions of your sandwich maker).
Medium toasted sandwich will take 3-4 minutes approximately.
Alternatively, you can toast the bread on a tawa, stuff it with the masala as in the previous step and serve.