Ganache is a glaze

Glaze (cooking technique)

A glaze in cooking is a coating of a glossy, often sweet, sometimes savoury, substance applied to food typically by dipping, dripping, or with a brush. Egg whites and basic icings are both used as glazes...

, icing

Icing (food)

Icing, also called frosting in the United States, is a sweet often creamy glaze made of sugar with a liquid such as water or milk, that is often enriched with ingredients such as butter, egg whites, cream cheese, or flavorings and is used to cover or decorate baked goods, such as cakes or cookies...

, or filling for pastries

Pastry

Pastry is the name given to various kinds of baked products made from ingredients such as flour, sugar, milk, butter, shortening, baking powder and/or eggs. Small cakes, tarts and other sweet baked products are called "pastries."...

  made from chocolate

Chocolate

Chocolate is a raw or processed food produced from the seed of the tropical Theobroma cacao tree. Cacao has been cultivated for at least three millennia in Mexico, Central and South America. Its earliest documented use is around 1100 BC...

 and cream

Cream

Cream is a dairy product that is composed of the higher-butterfat layer skimmed from the top of milk before homogenization. In un-homogenized milk, over time, the lighter fat rises to the top. In the industrial production of cream this process is accelerated by using centrifuges called "separators"...

.

Ganache is normally made by heating cream, then pouring it over chopped dark semi-sweet chocolate. The mixture is stirred or blended until smooth, with liqueur

Liqueur

A liqueur is an alcoholic beverage that has been flavored with fruit, herbs, nuts, spices, flowers, or cream and bottled with added sugar. Liqueurs are typically quite sweet; they are usually not aged for long but may have resting periods during their production to allow flavors to marry.The...

s or extract

Extract

An extract is a substance made by extracting a part of a raw material, often by using a solvent such as ethanol or water. Extracts may be sold as tinctures or in powder form....

s added if desired.

Depending on the kind of chocolate used, for what purpose the ganache is intended, and the temperature at which it will be served, the ratio of chocolate to cream is varied to obtain the desired consistency. Typically, two parts chocolate to one part cream are used for filling cakes or truffle

Chocolate truffle

A chocolate truffle is a type of chocolate confectionery, traditionally made with a chocolate ganache center coated in chocolate or cocoa powder, usually in a spherical, conical, or curved shape...

 base, while one to one is commonly used as a glaze. Cooled ganache can be whipped to increase volume and spread to cover a cake

Cake

Cake is a form of bread or bread-like food. In its modern forms, it is typically a sweet and enriched baked dessert. In its oldest forms, cakes were normally fried breads or cheesecakes, and normally had a disk shape...

. However, if left to cool too much it can become too thick and unspreadable.