Quiche-like, with added tang and color from the tomatoes. Lovely for lunch or Sunday night supper.
Melt chicken fat or butter and cook onions with thyme over very low heat until transparent (about 20 minutes). Beat eggs, and add milk and seasonings. Brush pie crust with egg white. Fill crust with onions, tomato, and cheese, and spread the egg mixture over the top. Bake at 400 degrees F for 10 minutes; lower heat and bake an additional 20 minutes at 350 degrees F. Serve warm.