Separate Egg (2) by cracking the shell over a bowl, and transferring the yolk back and forth between the halves of the shell. The white will drip into the bowl, and the yolk will remain in one half of the shell.
Place egg yolks in another bowl.
Place Unsalted Butter (7 tablespoon) in saucepan, and heat until melted.
Fill a saucepan with ten centimeters of water, and bring to a simmer.
Place bowl with egg yolks on top of saucepan.
Whisk yolks together.
Slowly add melted unsalted butter, whisking constantly.
Continue to whisk rapidly until mixture thickens and lightens in color.
Add Dijon Mustard (1 teaspoon), White Wine Vinegar (1 teaspoon) and whisk to combine.