Tranya was an orange to pink-colored beverage originating from the First Federation, usually served very cold.
It was first introduced to the United Federation of Planets in 2266, when Balok served it to officers of the USS Enterprise. (TOS: "The Corbomite Maneuver")
Tranya would later be a major export of the First Federation. Curzon Dax was particularly fond of the drink, and it was stocked in Quark's on Deep Space 9. (DS9: "Facets")
The tranya that Balok served the crew was, in fact, grapefruit juice, which young Clint Howard absolutely hated. He said in an interview that he had to work very hard at making it look like he actually liked it. (TOS Season 1 DVD special features)
"The Comedy Central Roast of William Shatner" implied that tranya could be an addictive beverage and that Balok had developed a bit of a drinking problem.
1 oz Coconut Rum (Malibu probably works best)
1 oz Peachtree Schnapps
.25 oz Amaretto
2 oz Cranberry Juice
2 oz Pineapple Juice
Mix the Coco Rum, the Peach Schnapps, Cranberry and Pineapple Juices, over ice.
Finally, float the Amaretto on the top and enjoy!