1½ tablespoons olive oil
1 red or white onion, sliced
3 teaspoons curry powder
1½ pounds lean boneless beef, cut into 1" cubes
½ pound fresh mushroom, sliced
1 tomato, diced
1 clove garlic, minced
2 teaspoons salt
2 teaspoons sugar
2 cups water
2 tablespoons cornstarch
2 tablespoons water

Heat oil in a heavy skillet. 

1. Sauté onion over medium heat, just until tender. 

2. Stir in curry powder, and cook 1 minute. 

3. Add beef cubes.

4. Add next 5 ingredients in order listed. 

5. Continue cooking until beef is lightly browned (do not be concerned that the skillet is dry because moisture will appear from the ingredients). 

6. Add enough boiling water to barely cover beef. 

7. Cover skillet and simmer gently for 1½ hours, or until beef is extremely tender.  

Thicken with 2 tablespoons cornstarch and 2 tablespoons water, mixed to form a paste.