Cook the cubed potatoes and other vegetables until all the veggies are tender but firm. Drain excess water and keep aside.
Heat a teaspoon of oil in a small pan and sauté the onions, green chili and garlic until slightly browned.
Switch off and add the sautéed onion, garlic and chilies to the veggies along with chopped mushrooms turmeric powder, red chili powder, garam masala and salt.
Let this cool completely and then mash slightly along with egg whites to make a thick mixture.
Take a small portion and roll them between your palms to make a ball, then press to flatten and shape as cutlet.
Spread a layer of breadcrumbs on a plate for coating and take each cutlet, place it on the bread crumbs to coat all sides.
Heat the oil in a pan for frying. Drop the coated cutlets in the hot oil and fry until its golden on both sides. (You can also pan fry the cutlets in a tawa.)