In medium saucepan, heat broth to boiling. Stir in couscous; cover and remove from heat. Let stand 5 minutes; fluff with fork. Set aside to cool slightly.
Grease 9-inch pie plate. Toss couscous with egg whites, parsley and Tabasco sauce. Spread mixture into bottom and up sides of pie plate. Set aside.
Preheat oven to 350°F. In 12-inch skillet, over medium heat, in hot oil, cook onion, squash, green pepper, corn, mushrooms and garlic about 5 minutes. Add tomatoes, Tabasco sauce, salt and basil; cook 5 minutes longer, stirring occasionally until liquid has evaporated.
Toss mixture with 1 1/2 cups cheese. Spoon mixture into couscous crust. Sprinkle with remaining 1/2 cup cheese. Bake 30 minutes or until crust is firm and cheese is melted.
580 mg sodium, 25 mg cholesterol