1. Heat olive oil in a 10-inch nonstick broiler-proof skillet over medium heat. Add zucchini, bell pepper, onion, thyme, 1/4 teaspoon salt, 1/8 teaspoon black pepper, and garlic. Cover and cook 7 minutes or until vegetables are tender, stirring occasionally. Stir in tomato. Cook, uncovered, for 5 minutes or until liquid evaporates.
2. Combine eggs, remaining 1/4 teaspoon salt, and remaining 1/8 teaspoon black pepper in a medium bowl; stir with a whisk until frothy. Pour egg mixture into pan over vegetables, stirring gently. Cover, reduce heat, and cook 15 minutes or until almost set in the center.
3. Preheat broiler.
4. Broil frittata 3 minutes or until set. Invert onto a serving platter; cut into 8 wedges.