2/3 cup chopped plum tomatoes
1/2 cup shredded part-skim mozzarella cheese
1/4 cup chopped Kalamata olives
1 teaspoon minced garlic
2 teaspoons extra-virgin olive oil, divided
1/2 teaspoon finely chopped fresh rosemary or 1/8 teaspoon dried
1/8 teaspoon freshly ground pepper
4 portobello mushroom caps, 5 inches wide
2 tablespoons lemon juice
2 teaspoons reduced-sodium soy sauce