Wash the zucchini, peel and grate them on a coarse grater. Then put them in a pot, pour in a little water and saute until softened. If there's any water left, drain it out well.
In a bowl, grate the feta cheese. Add the milk, the yolks of the boiled eggs and grated zucchini. Beat with a mixer, while gradually pouring in 5-6 tbsp oil or more, to taste.
To the resulting mixture, add the mashed garlic and salt to taste. Place round slices of tomatoes in serving plates, pour the prepared mixture on top with a spoon. Sprinkle each serving with chopped parsley and finely grated boiled egg whites.