Angostura Bitters and Grapefruit Whisky Sour

(11)
"Happy Friday everyone. We made it through what seems to be the longest week in the history of man. WOO. I've been inspired by @join_jules on @feedfeed.cocktails - follow both for some great cocktails. Here is my recipe for whisky and grapefruit sours. So easy, so delicious. All you need is grapefruit, whisky, sugar, angostura bitter and egg white."
-- @mysugarthumb

A Note from Feedfeed

Classic cocktail, this whiskey sour is enhanced with Angostura bitters (originated by House of Angostura in Trinidad and Tobago), perfect for cleansing the palate for an evening sip. Add some grapefruit for a bright citrus finish.