Preheat broiler to high. Combine egg whites, eggs, salt, pepper, and milk; stir with a whisk.
Heat a 9-inch cast-iron skillet over medium heat. Sauté grape tomatoes and thyme in olive oil until tender.
Layer in plum tomatoes and basil.
Sprinkle with crumbled goat cheese.
Carefully pour egg mixture over cheese. Cook over medium heat 5 to 6 minutes or until eggs are partially set; then broil 5 inches from heat for 2 to 3 minutes or until browned and almost set.
