Imagine a combination between egg nog and brandy and you will have something known in the world of spirits as Advocaat. While it is not very high in alcohol content, it is very high in flavor and is manufactured by several different brands. You may be able to find it in a few different locations both locally and online and can make a few cocktails with it if you don't want to drink it by its lonesome.
Advocaat is a creamy spirit that has the consistency of egg nog, which is made from brandy, eggs and sugar. It tastes much like custard and will typically be around 30 proof (15% alcohol) throughout English-speaking countries. There are some areas of Europe where you may be able to find it wish as high as 20% alcohol. Some additional ingredients often blended into the spirit includes:
Each brand will make it a little different, however the flavor is always a custard-like tasting spirit that has a smooth, creamy texture that goes down well just chilled (or over ice) or mixed into one of many different cocktails.
There are several brands that make Advocaat including Bols, Warners, and De Kuyper so you may be able to find it right at your local liquor store. It is usually kept in the same section as flavored egg nogs, Cream liqueurs or anywhere else. The chances of your liquor store having it year round is unlikely, unless it's a very large store. Otherwise, many will bring it in around the holidays because that is when it is commonly served.
If your local liquor store doesn't have Advocaat, you should be able to locate it in most online liquor stores. This is because they are able to have more variety since there are no overhead store costs. A quick e-mail to the store will help you to find a place to get it if you still aren't having any luck. Find a brand that carries it and try going at it from that angle.
Advocaat is tasty enough on its own so you don't have to add anything to it to enjoy its flavors. There are many cocktails you can make with it, though, that can be very rich and tasty. Two of the most common ones are the Russian Snowball and the Trifle Shot.
The Russian Snowball is made by taking a tall glass and adding a shot each of the custard liqueur and Citron vodka. You will then add a dash of lime juice and fill the rest with lemonade. Stir the ingredients with a little ice and enjoy. The other will taste just like the English trifle dessert. It's made with equal parts of the liqueur, Fraise de Bois, and whipped cream (the kind in the can). Layer the Advocaat and Fraise de Bois in a shot glass and top with the whipped cream. Then add a few hundred chocolate sprinkles and you've got a delicious shot.