Steam or boil 3 to 4 medium potatoes till they are cooked completely. Once they become warm, then peel and mash them. Keep aside. You can steam or boil potatoes in a rice cooker, pressure cooker, pan or a steamer. If using a pressure cook, then pressure cook for 7 to 8 minutes in 1.5 to 2 cups water.
In a mortar-pestle, take ½ inch ginger (chopped) and 1 or 2 green chilies (chopped).
Crush to a coarse or a semi-fine paste.
Heat ½ tablespoon oil in a pan. Add ½ teaspoon mustard seeds and let them crackle.
Once the mustard seeds crackle, then add ½ teaspoon cumin seeds.
Let the cumin seeds also crackle and splutter.
Now add the crushed ginger-green chili paste. Saute till the raw aroma of ginger goes away.
Next add 8 to 10 curry leaves (whole or chopped) and a pinch of asafoetida. Mix well.
Now add the mashed potatoes, turmeric powder and salt.
Mix very well and saute for a minute.
Lastly add ⅓ cup chopped coriander leaves - you can add ¼ cup too.
Again mix very well. Switch off the flame and keep the pan aside. Let the potato stuffing become warm or cool down.
preparing sandwich chutney and other toppings
Rinse coriander leaves very well in water.
Then in a grinder take 1 cup tightly packed coriander leaves, ½ teaspoon chaat masala powder, 1 to 2 green chilies (chopped), salt. Add 1 to 2 teaspoons water. Grind till smooth. Remove the chutney in a bowl and keep aside.
Grate cheese and keep aside. You can use cheese as required. You can use processed cheese, cheddar cheese or mozzarella cheese. I have used ⅓ cup grated processed cheese.
Slice thinly 1 medium onion, 1 medium tomato, 1 small to medium cucumber and 1 small to medium capsicum. Keep aside. You can also use boiled beetroot.
assembling and grilling cheese masala toast sandwiches
Take the bread slices. Trim the edges if you want. Spread butter evenly and generously on the slices. Applying butter very well, does not make the sandwiches soggy when chutney is spread on them.
Now spread the green chutney as per your requirements.
Place a few slices of onion and tomato.
Sprinkle some black salt and chaat masala. You can use rock salt or regular salt if you do not have black salt.
Now spread the potato masala on the sandwich.
Top with thinly sliced capsicum (green bell pepper) and cucumber.
Again sprinkle some chaat masala and black salt.
Now top with grated cheese.
Place the buttered bread slices.
Now carefully, place the sandwiches in a preheated grill or sandwich maker. Close the cover and grill till the sandwiches are crisp and golden. Do not press the top cover too much as then the cheese melts and drips down.
Once the sandwiches are toasted well, remove and place in a plate or tray. Spread some butter if you want on the toast sandwiches.
Serve mumbai cheese masala toast sandwiches hot or warm with green chutney and tomato ketchup.
Notes
Recipe can be doubled
You can add less or more green chilies as per your preferences in the sandwich chutney.
Veggies like onions, capsicum, cucumber and tomatoes can be skipped as per your choice.