Bourbon Whiskey

American's don't need to be lectured on Bourbon, but still, let's put it in record like all other spirits. A Bourbon in American spirit is a barrel-aged distilled liquor made primarily from corn. The name might have been derived from the French Bourbon dynasty, or from Bourbon County in Kentucky, or Bourbon Street in New Orleans, both named after the French Dynasty.

Technically, most whiskey made in America are legally classified as Bourbon, although Bourbon is in spirit a Southern Whiskey with special connection to Kentucky. Note than although Tennessee Whiskey is classified as Bourbon, Tennessee distilleries do not prefer their whiskey to be unique and referred to as Tennessee Whiskey only.

Distilling came to Kentucky in the late 18rth Century with the Scots, Scot-Irish and other settlers including English, Welsh, German and French, and they brought with them their distilling techniques and ageing processes in charred oak barrels. The charring is what gives the Bourbon the brownish colour and distinctive taste.

To be a legal Bourbon, a whiskey has to meet the following criteria

Produced in the United States and Territories (Puerto Rico) and the District of Columbia
Made from a grain mixture that is at least 51% corn
Aged in new, charred oak containers
Distilled to no more than 160 (U.S.) proof (80% alcohol by volume)
Entered into the container for aging at no more than 125 proof (62.5% alcohol by volume)
Bottled (like other whiskeys) at 80 proof or more (40% alcohol by volume)

Brown Creme De Cacao

Creme de Cacao is a chocolate liqueur that has probably been produced and sold in France since as early as 1666. In America a Chocolate wine was popular in the 18th Century, it's ingredients included sherry, port, chocolate and sugar.

A modern recipe for chocolate liqueur at home lists the ingredients as chocolate extract, vanilla extract and simple syrup and in purest form, chocolate liqueur is clear and colours may be added.

Creme de Cacao can be consumed straight and as an apertif, in cocktails and in desserts, in dessert sauces, cakes and truffles.

Vanilla Bean

Vanilla is a spice derived from orchids of the genus Vanilla, the spice is obtained from the pods of the Mexican species of flat leaved Vanilla. The characteristic flavour of Vanilla comes from the aromatic compound Vanillin. Up to 85% of a vanilla essential oil is Vanillin.
Natural vanilla flavour is in pure form, a little more complex than plain Vanillin, but most of the times the Vanillin is what is needed to release that familiar flavour in a drink.
Note that when a drink asks for Vanilla extract, it means an extract of real Vanilla from Vanilla pods in an alcoholic suspension and is usually less processes and stronger, while Vanilla Flavour or Vanilla Essence is a processed product made using artificial flavours and colours. While a Vanilla syrup is a sweetened thick condiment with either real organic vanilla flavour or artificial vanilla flavouring.
The thumbs rule is, if you run out of Vanilla extract, go for Maple syrup as a replacement. Also note that artificial vanilla is strong and artificial vanilla flavour comes from Castoreum, a chemical compound that comes from a beaver's castor sacs, which are located between the pelvis and the base of the tail.