Halve about 1-1/2 cups of the tomatoes; set aside. Lightly coat a 10-inch nonstick skillet with olive oil cooking spray. Add shallots, garlic, and lemon-thyme. Cook and stir over medium heat for 2 to 3 minutes or until shallots are tender. Add all of the tomatoes, the salt, and pepper. Cook and stir for 1 to 2 minutes more or until tomatoes are just warmed.
Remove from heat. Stir in mozzarella cubes. Makes 4 side-dish servings.