Get some slices of old bread. Smear them with butter. Beat the egg with the crumbled feta cheese, grate the cheese. Cut any leftover meats found in the refrigerator (ham, bacon, lard salami), into strips or cubes.
On the bread slices, distribute the products as you like - you can make sandwiches with just egg and cheese or with sausage and cheese, or sausage and egg and cheese. You have the freedom to choose.
Arrange the sandwiches in a baking dish, add some olives and pieces of butter between the slices. Bake in a preheated oven until ready.
Fast, easy and delicious!