Preheat oven to 375 degrees . Mix sour cream, eggs, and cheese. Stir in scallions, tomatoes, and salt and pepper. Lay avocados on bottom of pie shells. There should be just enough slices to cover the bottom. Pour cheese mixture over avocado slices and spread out evenly. Bake until set, golden, and puffy, about 40 to 45 minutes. Let stand 10 minutes before serving. Top with a spoonful of fresh avocado, tomatoes, and scallions. Add a dollop of sour cream on top.