Neatly sort out the spinach leaves, rinse them carefully and blanch them briefly in boiling hot salted water. Rinse in ice-cold water and squeeze well.
Separate the eggs. Whip the egg whites to stiff peaks and set aside to cool. Soak the white bread in milk.
Remove the skin from the onion and finely weigh it with the spinach leaves. Melt the butter in a bowl and sauté the spinach and onion mixture in it. Stir in the squeezed out white bread and gradually fold in the egg yolks and the diced ham. Finally, gently fold in the well-chilled snow.
Grease a cooking pudding mold with butter and sprinkle with breadcrumbs. Fill the quantity into the pudding mold, close it well with the appropriate lid and cook in a water bath for one hour.
In the meantime, melt the butter and fold in the flour.
Pour in boiling beef broth, boil thoroughly and whisk until creamy. Add the egg yolk and season with a little salt and the juice of a lemon.
Remove the pudding and let it rest briefly. Then turn it out onto a flat, preheated plate and pour butter sauce over it.
(*) The sauce must be quite thick. Therefore, it is advisable to pour a little beef broth first and add a little more if necessary.
Tip: Did you know that one bowl of spinach already covers the entire daily requirement of vitamin K and beta-carotene?