Apply butter on all 4 slices of bread. Keep aside.
Mash boiled poatoes. Chop onion, green chilli and coriander leaves. Peel and grate ginger.
Heat oil in a wok. Add cumin seeds and when cumin seeds splutter put finely chopped onions and grated ginger and fry till golden brown colour. Add green chilli and mix. Add salt, turmeric, red chilli & black pepper powder and cumin seeds powder and mix.
Add mashed potatoes and mix well. Saute for 2 minutes and switch off the flame. Add chopped coriander leaves and mix. Let it cool.
Now apply butter on 2 bread slices. Spread this 2 tb sp potato stuffing on buttered slices. Place a cheese slice over it. Now cover it with other 2 bread slices. Then apply butter on it .
Now Grill it for 7-8 minutes
Slice the sandwich and serve hot with tomato ketchup.
