How to make
Prepare the beetroot by washing it well under running water. Spread it with a little oil and wrap it in aluminum foil. Bake at 390°F (200°C) for about an hour. Test it with a fork and if it still seems hard, bake it, until it's done.
Peel and cut the potatoes into thin slices, salt them and sprinkle them with black pepper. Arrange them in a baking pan, by covering the bottom and sides with a layer or two.
Drizzle a little olive oil on the edges and spread the butter in pieces on the base. Bake at 370°F (190°C) for about 30 minutes, or until it aquires a golden brown color.
Meanwhile, prepare the spinach stuffing by chopping the leeks and stewing them with a pinch of salt, until they soften in olive oil. Add spinach, chopped or whole leaves - whatever you prefer. Cook for 4-5 minutes and remove it from heat.
Cut the prepared beetroot into slices and arrange it on top of the potatoes in one layer, sprinkle a little salt and black pepper and spread the spinach filling.
Beat the eggs for the topping with the yogurt and crumble the cheese inside. Pour over it the dish and bake, until it aquires an appetizing color (390°F (200°C)), then grate the yellow cheese (or Gruyère cheese) as a finishing touch and put it back in the oven for a short while, until it melts and forms an appetizing golden crust.
Serve the casserole warm and enjoy its wonderful taste.
The wonderful casserole with beetroot, potatoes and spinach is ready.