Steam your potatoes in the microwave for 3 minutes and wait for it to cool down. Peel off the skin and chop into tiny cubes.
Slice tomatoes and keep aside.
Wash your coriander and mint leaves and break off the large stems (you can use it to make veggie broths or herbal water). Add them to a blender.
Add the rest of the ingredients to a blender - ginger, chili, lemon juice, pumpkin seeds, salt. Blend. If the mixture is too thick and unable to blend, just add a splash of more water.
Layer your sandwich with butter, green chutney and the other slice with tomato ketchup. Add sev, chili flakes, potatoes, tomatoes and shredded vegan cheese. Top with some chaat masala and cover with the other slice of bread.
Butter the side of the bread that is facing you.
Transfer this to a pan to toast side of the buttered bread. While toasting, spread some butter on the other side, and toast them for a few minutes on both sides.
Cut the toast diagonally into half and munch on these addictive sandwiches! If you're making this for a party as an appetizer, you can cut them up into small squares for easier snacking.