|Butter||6 Tablespoon, cut in small pieces|
|Lemon juice||1 Tablespoon|
|Dijon mustard||1 1⁄2 Teaspoon|
|Whipping cream||3 Tablespoon|
Melt 1 teaspoon of butter in a small saucepan.
Stir in the flour and cook over medium heat for 3 minutes, stirring constantly.
Do not let the mixture brown.
Add the milk, whisking until the cream sauce is thick and smooth.
Whisk the egg yolks, lemon juice, and whipping cream over medium heat just until the mixture begins to thicken.
Remove from the heat and gradually add the 6 tablespoons of butter, whisking constantly.
Add salt and cayenne to taste.
Stir in the mustard and the reserved cream sauce.