Dry roast the whole spices for masala on medium-low heat with stirring constantly.
As you get the nice aroma of the roasted spices, turn off the stove and remove it to plate to cool completely.
Once cooled take into the grinder jar along with black salt and amchur powder and make into fine powder. Keep it aside.
Making Chutney:
Take all the chutney ingredients in the grinder along with very little water and make smooth puree.
Remove it to a bowl and keep it aside.
Making Sandwiches:
Keep all the veggies, cheese, chutney, bread, butter and sandwich masala ready before start assembling it.
Heat the grill pan on medium heat. While it is heating assemble the sandwich.
take 3 bread slices for one sandwich. Spread butter and chutney on each slices.
Now place the vegetables in this order: potato, cucumber, onion, second bread slice, capsicum, tomato, cheese. Don't forget to sprinkle sandwich masala on each and every vegetable layer.
Lastly close with last bread slice, chutney side down.
Place the sandwich carefully on the grill pan or machine and grill till it is crispy and golden brown.
Then flip and grill other side as well. If using machine then no need to flip as it grills both sides at the same time.