Clean the mushrooms with a damp cloth, wiping dirt from the stems and caps. Finely mince them. Mince the other vegetables. Dice the onion.
Heat the oil in a large heavy skillet over medium-high until hot. Add the minced mushroom and onion. Sprinkle with a little of the salt. Cover. Let cook undisturbed for 1-2 minutes. Stir.
Continue to cook until the mushrooms and onions are very soft and browned. Stir in the other vegetables including hot chiles. Cover and let cook 1-2 minutes. Stir. Add a few tablespoons water if necessary to keep from sticking and burning.
Add the spices and ketchup. Cook until vegetables are tender. Stir in chopped walnuts. Serve.
I’ve used cauliflower florets and stems, broccoli stems, summer squashes or a combination of those – use whatever you have on hand