Preheat oven to 350°F. Cut each toasted bread slice into 4 squares; place in single layer on baking sheet.
Cut each cheese slice into 4 squares. Place 1 cheese square and 1 tomato slice on each bread square. Season tomatoes with garlic salt. Arrange olive slices over tomatoes. Drizzle lightly with oil.
Bake 7 to 8 minutes or until cheese melts. Garnish with basil. Serve warm.