1. Whisk together whole eggs, whites, 1/4 cup parmesan, basil, 1/2 teaspoon salt, and 1/4 teaspoon pepper in large bowl.
2. Preheat broiler.
3. Cook garlic in 1 tablespoon oil in a 10-inch heavy skillet (preferably nonstick and ovenproof) over moderate heat, stirring, until golden, about 1 minute. Transfer garlic with a slotted spoon to a bowl.
4. Add potatoes to skillet and saute over moderately high heat, stirring, until just tender, about 6 minutes. Transfer with a slotted spoon to bowl with garlic.
5. Add 1 tablespoon oil and tomatoes to skillet and cook over moderately high heat, stirring, until tomatoes brown and skins split, about 4 minutes.
6. Add remaining tablespoon oil and potatoes with garlic to skillet, spreading evenly, and sprinkle with remaining 1/4 teaspoon salt and 1/4 teaspoon pepper.
7. Pour egg over vegetables and cook over moderately high heat, lifting up cooked egg around edges to let uncooked egg flow underneath, 3 minutes. Reduce heat to moderate and cook, covered, 5 minutes more (center will be moist).
8. Remove lid and broil frittata 5 to 7 inches from heat until set, about 5 minutes. Sprinkle top evenly with remaining 1/4 cup parmesan, then broil until cheese melts and frittata is golden brown, 2 to 3 minutes more.
9. Slide onto a platter and cut into 4 wedges.

Yield: 4 servings