Mexican Fiesta Stew

2 tablespoons vegetable oil
3 pounds boneless beef round or chuck steak,
    cut into 1-inch chunks
1/2 teaspoon salt
1 cup salsa
1 cup beef broth
2 medium zucchini, cut into 1/2-inch chunks
1 (15 ounce) can black beans, rinsed and drained
1 (8 3/4 ounce) can whole-kernel corn, drained
2 tablespoons cornstarch
3 tablespoons water

In a soup pot, heat the oil over medium-high heat until hot; add the beef and brown evenly. Drain off the liquid, add the salt, salsa, and broth, and bring to a boil. Reduce the heat to low, cover, and simmer for 1 to 1 1/4 hours, or until the beef is tender.

Add the zucchini, beans, and corn; cook for 15 to 20 minutes.

Dissolve the cornstarch in the water and add to the stew. Cook for 1 minute, or until thickened, stirring constantly.

Serve with bowls of toppers including chopped tomatoes, shredded cheese and sour cream.