Preheat grill or broiler.
Combine olive oil and TABASCO® Sauce in small bowl.
With paring knife, cut stems off the Portobello mushrooms so that they are flush with the caps; wipe clean with damp paper towel. Brush mushrooms on both sides with TABASCO® mixture. Cook mushrooms three minutes; turn. Brush with remaining mixture. Cook four minutes or until mushrooms are tender.
Remove mushrooms to serving plate. Layer with sliced tomatoes and mozzarella cheese; tuck in basil sprigs.
Makes four burgers.