Begin with the hollandaise sauce.

Melt 200 grams of butter in a double boiler, then set aside.

In another saucepan, beat the egg yolks with a tablespoon of lemon juice, a tablespoon of cold water and a pinch of salt for a few seconds, then cook in a double boiler with 15 grams of cold butter. The water should just simmer. Whisk the egg yolks for a few minutes until they begin to thicken. When the yolks have thickened enough to see the bottom of the pan when whisking, remove from the heat and add the last 15 grams of cold butter. Whisk the egg yolks to melt the butter, then add the melted butter drop by drop, whisking constantly, until the yolks do not become a thick sauce. Now add the remaining butter, stirring constantly. Season with salt, pepper and more lemon juice if necessary.

Keep the hollandaise sauce aside and prepared the spinach. Rinse them well, collect them in a pan with milk, a pinch of salt and grated nutmeg, cook them on medium-low heat for about 10 minutes, until softened.

Now poach the eggs. Heat a pot of water and when it takes a gentle simmer, add the vinegar. The water will be warm and quivering slightly, it won't be in a rolling boil. Break the eggs into four coffee cups, stir the water with a spoon to create a vortex, and pour inside the vortex an egg. The egg white will the egg yolk. Poach for about 2 minutes, then lift it with a slotted spoon and put the poached egg onto some kitchen paper. Repeat with the other eggs.

In each dish place a slice of toasted bread cover with the milky spinach, add the poached egg and drape with hollandaise sauce.