Heat 1 Tbsp. oil over high heat in skillet. Braise meat in skillet, remove and season both sides with the salt, chili powder and pepper. Put meat in baking dish with 1/4 cup water.
Preheat oven to 350. Cover and bake meat at 1 1/2 hours til tender. Remove, trim fat and cut across grain into 1/2 inch thick slices. Return meat to baking dish and let stand in juices.
Heat 2 Tbsp. oil in skillet. Add the sliced red onion, sliced green bell pepper and sliced mushrooms. Sauté til onions are soft. Mix in the sliced tomato and tomato sauce. Cook 5 more minutes. Serve with meat.
Mexican rolls go great with this dish. Also, rice.