Cherries are usually a standard garnish on cocktails, but quite often, the cherry will be one of those artificially flavored, bright red maraschino cherries that lack any depth of flavor and taste like candy. However, do not fret, you can make delicious, spirit laden cherries which are rife with flavor rather easily.
The cherry pictured above, as you can guess, is a maraschino cherry: the color stands out, is an unnatural and brilliant red, which does not belong to any varietals of cherries naturally. Below is a maraschino cherry of my own. Notice that the coloring is a light pink, with spots of red, mostly because the color seeps out unless you use something to preserve or dye the cherry, such as hibiscus syrup.
As Robert Hess claims, a maraschino cherry prior to the Prohibition was very similar to a brandied marasca cherry; as such, the simplest way to make these would be to pit the cherries, lightly cook them in a sugar syrup solution, and then bottle them in brandy. Even simpler would be to just put the cherries in a jar with brandy and a tad bit of sugar. These are excellent in either case, but are extremely alcoholic.
In order to do my own little variation, I took a red wine syrup, cooked the cherries in that, and then re-bottled the cherries with some brandy mixed in the red wine syrup. The syrup gives them extra flavor, and helps to preserve the color. This syrup is great: essentially, combine over low heat one part red wine (in this case, I used a fortified wine of Maurin) and one part sugar. For this, to give it some more depth of flavor, I used demerara sugar. You could also use a cherry juice syrup, which will instill and help it retain the red hue, and imbue a true “cherry flavor” to the candied cherries. Luxardo Marasca cherries are sitting in a Marasca cherry juice syrup.
The other thing you could do is take dried cherries and plump them by cooking them in a sugar syrup, giving them a bit of body and volume, as seen in the below picture. The problem with this are even though the cherries will plump decently, they will be exceedingly sweet; these make for good dessert cherries, but not exceptional cherries as a whole. But it is easier to do than to pit a bunch of cherries, sorting the good from the bad, and adjusting the recipe to taste repeatedly over a stove.
Overall, either of these methods are far tastier than using store bought maraschino cherries, and can be much cheaper than buying a small jar of marasca cherries. The other way to make cocktail cherries is to take a spirit, and just macerate the cherries in that spirit, with some added sugar, letting it sit in a jar for an extended period of time until it absorbs the flavors desired and then until you wish to use the cherry. This method is by far the simplest, and is now the one in which I turn to as the best. They produce solid, darkly colored cherries that have an inherent appeal without being overly sweet, or artificial flavored.