Prepare the vegetable patty by mixing 200 grams of boiled and mashed potatoes, 100 grams of grated paneer, 50 grams of boiled and mashed peas, 1 finely chopped green chili, 1 teaspoon of grated ginger, 1 teaspoon of garam masala, 1/2 teaspoon of red chili powder, 1/2 teaspoon of chaat masala, salt to taste, and 2 tablespoons of chopped coriander leaves. Mix well and form 4 equal-sized patties.
Coat the patties with a mixture of 2 tablespoons of cornflour and 4 tablespoons of water, and then roll them in breadcrumbs. Shallow fry the patties in medium-hot oil until they are golden brown and crispy. Set aside.
Slice 4 burger buns horizontally and toast them on a tawa or griddle with a little butter until they are slightly crispy.
Assemble the burger by spreading 1 tablespoon of mayonnaise on the bottom half of each bun, followed by a layer of lettuce leaves. Place the vegetable patty on top of the lettuce, and then add a slice of tomato and a slice of onion.
Spread 1 tablespoon of tomato ketchup and 1 tablespoon of green chutney on the top half of each bun, and then place it on top of the assembled ingredients.