I use cognac in this recipe and find it divine.
Alice Waters says: "Get the best cherries and the best brandy you can afford, or use kirsch if you like. This method works for either sweet or sour cherries, but do not use soft or overripe fruit. Cherries preserved unpitted and with stems on have the best flavor and are pretty served whole. Cherries to be used for such things as ice cream are better preserved after being stemmed and pitted; save the pits to put in the bottom of the brandy jar for more flavor.
"For each pound of cherries, mix 2 cups brandy or kirsch with 1/2 cup granulated sugar. Add a few tablespoons more sugar per pound if you have doubts about their sweetness; for sour cherries, use 3/4 cup sugar per pound. Rinse the fruit in cold water, drain well, and stem and pit them, if desired. If you leave the stems on, you can trim them quite short. Put the cherries in a quart jar with a tight-fitting lid. Stir the brandy mixture and pour over the fruit. Cover tightly and keep in a cool part of the kitchen or in the cellar for at least 1 month before using. For the first week, turn the jar upside down daily to help dissolve the remaining sugar crystals. Refrigerate after a month. The cherries will keep for several months more."