Preheat oven to 400°.
Heat 1 tablespoon oil in a 9-inch cast-iron skillet over medium heat. Add Italian seasoning and garlic; sauté 1 minute. Arrange tomato slices in a circular pattern in skillet. Sprinkle with salt and pepper. Reduce heat to low.
Combine flour and next 7 ingredients (flour through cheese) in a large bowl. Add milk, ketchup, 2 tablespoons oil, and egg whites, stirring until moist. Pour batter into skillet. Bake at 400° for 30 minutes or until a wooden pick inserted in center comes out clean. Place a plate upside down on top of skillet, and invert onto plate.