Butter is a solid, pale yellow daiy product made from mechanically agitating fresh or cultured cream. Cream contains microscopic globules of butterfat as an emulsion. Agitating the cream damages protein and phospholipid membranes around the butterfat, which brings them together as a solid, and separating them from the water phase of the cream. The mass of butter is then kneaded to remove small  pockets of "buttermilk" (which is not what we know today as buttermilk, but rather the liquid left over from the process of making butter). Sometimes, the fresh butter is salted, then packed into molds to form one-quarter pound sticks.

Butter is ancient, and dates back to the domestication of livestock. It is one of the primary cooking fats around the world, featured strongly in the cuisines of India and France, where is it celebrated in everything from Hollandaise sauce to croissants. Butter melts quickly when heat is applied to it, and when used in baked goods, contains just enough air to provide lift to flaky pastries.

In cocktails, however, butter is almost impossible to use. Adding solid butter to the cocktail shaker is asking for trouble, and melting the butter is no better - it solidifies almost instantly upon contact with ice or other cold liquids. Butter is almost exclusively used to make Hot Buttered Rum, where it is turned into a batter of sorts with spices and brown sugar, which is then topped with rum and hot water to make a winter drink. 

Some popular cocktails containing Butter

  • Hot Buttered Rum - Triobar — Dark rum, Apple juice, Butter, Vanilla Sugar, Cinnamon
  • Pearl Diver — Gold rum, Demerara Rum, Bitters, Crushed ice, Lime juice, Orange juice, Honey, Butter, Cinnamon syrup, Donn's Spices #2
  • Hot Buttered Amaro — Ramazzotti, Applejack, Cider, Butter, Orange peel
  • Cure for Eric — Rum, Virgin Islands Rum, Ginger liqueur, Bitters, Water, Pineapple juice, Orange juice, Butter, Lemon juice, Honey, Grade B maple syrup, Lemon zest, Vanilla extract, Nutmeg, Cinnamon, Cayenne pepper, Cinnamon stick, Cloves
  • Hot Buttered Rum — Dark rum, Water, Butter, Brown sugar, Cinnamon
  • Polynesian Pearl Diver — Puerto Rican Rum, Demerara Rum, Jamaican rum, Falernum, Allspice Dram, Orange juice, Lime juice, Butter, Honey, Vanilla syrup, Cinnamon syrup