"Named by Isolt Sayre after the great horned river serpent that has a jewel set into its forehead; Horned Serpent house is sometimes considered to represent the mind of a witch or wizard. It is also said that Horned Serpent favours scholars." - Pottermore
1 oz bourbon
1 tsp fresh cranberry juice 1 oz crème de cacao 1 oz half and half One egg white
Combine ingredients in shaker, add ice, shake and strain into a glass. Garnish with whole cranberries and a sprig of rosemary!