Crème au Beurre

This buttercream was created by a pâtissier called Ouillet around the early 19th century and originally named after him as crème à Ouillet, it later changed to simply crème au beurre. There are many recipes and methods to make buttercream but the original recipe by Ouillet was made in the same way as this recipe, where a sugar syrup is streamed onto whisking egg yolks, then softened butter is beaten in when it is cooled.