Heat oil in a large nonstick skillet; cook the beef, onion and garlic over medium heat until meat is no longer pink, 5-6 minutes; drain. Stir in tomato sauce and rosemary; bring to a boil. Reduce heat; simmer, uncovered, until thickened, 6-9 minutes., Place pita halves, cut side up, on a baking sheet. Top with meat mixture, tomato, spinach and olives. Sprinkle with cheeses. Bake at 400° until cheeses are melted, 4-6 minutes.