Hollandaise sauce: Place a saucepan with water and a glass bowl on top on the heat.
The bottom of the glass bowl should just touch the water.
Bring the water to a gentle boil.
Whisk the yolks with the water, vinegar, and lemon juice, seasoning with pepper and salt.
Now whisk vigorously over the lightly boiling water until it forms a thick foam.
This way, you don't have to clarify the vegetable margarine.
Add the vegetable butter piece by piece while whisking, taste and season if necessary.
Turn off the heat and you can keep the mousseline warm in the hot water.
Toast the 4 slices of bread, place the slices of smoked salmon on top, followed by the spinach leaves.
Poaching the eggs: Place a deep pan on the heat, fill it with water, and add a generous splash of vinegar.
Bring it just below the boiling point and maintain a gentle bubbling throughout the cooking time.
Carefully crack the eggs into bowls and gently pour them into the water, adjusting the heat if it gets too vigorous or too quiet.
Let them cook for 3 minutes.
In the meantime, you can gently scoop the edges of the egg white with a fork over the egg to give it a round shape again.
Scoop out with a spoon and dab on a towel.
Place on top of the spinach and finish with a generous spoonful of hollandaise sauce on top.