Place eggs, key lime juice and sugar into a shallow saucepot and whisk to combine. Place on the stove top and turn the heat to medium. While the mixture is still cool, place the cubed butter into the pan—it will combine as it melts. Whisk the mixture until it becomes thick and bubbly, about 8-10 minutes. Once it begins to thicken, remove from the heat and chill for at least an hour or overnight. Once the curd is cooled, stir in the tequila and orange liqueur.
Crush two vanilla wafers into the bottom of a 4-ounce jar. Top it with a spoonful of lime curd. Repeat twice more to fill the jar. Place the jars into the fridge until ready to serve.