When I use the word "loaded" here it's a non-sexual double entendre. Monte Carlo, part of the city-state of Monaco, is loaded in that it has a ridiculous amount of money. The Monte Carlo cocktail is loaded in that it can make you very drunk if you're not careful. Making its grand entrance in 1948 in David Embury's book The Fine Art of Mixing Drinks, the Monte Carlo is simple and sophisticated.
Combine in a mixing glass with ice, stir as if you're suave and rich enough to gamble in Monte Carlo's legendary casino (think James Bond in Goldeneye), and strain into a chilled glass, preferably over a large ice cube.
The Benedictine DOM, a rich French herbal liqueur used in drinks such as my Whiskey Queen, is the key ingredient in the Monte Carlo or its variations. Depending on your perspective, the Benedictine substitutes in for the super simple syrup in an Old Fashioned, or the sweet vermouth in a Manhattan. How dry or sweet you prefer the Monte Carlo depends on the ratio between the rye and the Benedictine. Not into rye? Use bourbon (a Kentucky Colonel), reposado or anejo tequila (a Monte Carlos), or some other aged spirit.
Want to gamble like a Millionaire? A Monte Carlo will make you feel loaded.