Butterscotch Schnapps

Schnapps is an alcoholic beverage that can be a distilled fruit brandy, a herbal liqueur, infusions and flavoured liqueurs, made by infusing fruit syrups, spices or artificial flavourings to a neutral grain spirit.

Schnapps in German means a strong alcoholic drink and it's usually a 60-80 proof (30% - 40% ABV) beverage.

Butterscotch Schnapps is a Schanpps made by infusing butter and brown sugar in grain spirit, and is designed to taste just like butterscotch caramels and are used in creating sweet cocktails and shots. It is usually 30–42 proof (15% – 21% ABV ) and is weaker than other Schnapps.

The most famous Butterscotch Schnapps is Dekuyper Buttershot Schnapps.

Coffee

Coffee or roasted coffee beans brewed in hot water, is the most popular drink that probably competes only with tea in the non-alocholic beverages category. Coffee being a rich source of caffeine it can help the human body overcome fatigue and improve physical performance and also lower risks of several conditions like Type II Diabetes, Cancer and Alzheimer's and Parkinson's disease.
Coffee liqueur is a popular and brands like Kahlua and Tia Maria are regulars in cocktails, but often brewed non alcoholic coffee is used in cocktails too, hot black coffee with Rum and whipped cream is what makes a Troical Coffee Cocktail for you, and being a caffeine rich liquid, it is a strange combination with alcohol since it tends to interact with the body and do just the opposite of what alcohol does, that it, tries to keep you alert and awake.

Milk

Milk can do wonders to your regular cocktail. For a rich creamy cocktail, milk does wonder .You may argue that milk as it is made of fat, and being low in acid, will easily curdle if its mixed with alcohol.
Best way to get a rich and creamy cocktail is to use bourbon, milk will soften its whiskey flavour. If you are looking for some spicier yet creamy cocktail go for Scotch with milk cocktails, they'll surely set you holiday mood.

Sugar

Brown Sugar is a sucrose sugar with a distinctive brown colour from the presence of molasses, it is a partially refined or unrefined sugar containing sugar crystals and residual molasses giving it a distinctive taste and flavour of crystallised molasses or toffee. The taste of dark brown sugar is described as a caramel taste with a deep molasses flavour.
Brown sugar is used in cocktails where a caramel candy or toffee flavour is expected.

Caster Sugar is finely ground granulated sugar. It is not as fine a powdered confectioners' sugar and has a little grit to it. It is somewhere between confectioners' sugar and granulated sugar, and melts in mouth with a mild spicy feel to the tongue

Vanilla Sugar is the regular granulated sugar infused with vanilla flavour, by using vanilla pods and seeds to flavour the sugar. A home made alternative is to use vanilla sticks or pods in a jar of sugar and leave it sealed for 4 weeks to allow the vanilla flavour to infuse. Or to use granulated sugar and vanilla extract and blend in a mixer, although this ends up in powdered sugar.

Kahlua Coffee Liqueur

Coffee liqueur is a liqueur produced by steeping roasted coffee, sugar and other ingredients in neutral spirit. The most famous coffee liqueur brands are Kahlua and Tia Maria, Kahlua has been made in Mexico since 1936.

However Kahlua has a thick buttery taste, that doesn't always appeal to the preferences of an alcoholic beverage lover. Which is why many people enjoy coffee liqueur made using their own home recipes.

Typical ingredients of coffee liqueur include liquor, espresso coffee, roasted coffee bean (and powder), sugar, and vanilla syrup.

The characteristic flavor of coffee along with over a couple of hundreds compounds contribute to the taste of coffee liqueur. Caffeine is a major ingredient of coffee, and also might be a taste factor that influences the complex flavour profile that appeal to coffee liqueur drinkers' palate. Reference - International Journal of Engineering & Advanced Technology (IJEAT)

NOTE: In the absence of a Coffee Liqueur like Kahlua or Tia Maria, to make cocktails with Coffee Liqueur, Coffee Liqueur Syrup can be used as a substitute with the proportionate alcohol substituted with a triple distilled neutral Vodka.