Vegetable oil spray, for misting the pan
Flour, for dusting the pan
1 package (18.25 ounces) plain yellow or lemon cake mix
Half a package (3.4 ounces) vanilla instant pudding mix (4 tablespoons)
1/3 cup granulated sugar
2/3 cup water
½ cup vegetable oil
1/3 cup fresh lime or Key lime juice
¼ cup tequila
2 tablespoons triple sec
1 teaspoon grated lime zest
4 large eggs
For the glaze and garnish:
1 ¼ cups confectioners’ sugar, sifted
1 tablespoon tequila
1 tablespoon triple sec
1 tablespoon fresh lime juice or Key lime juice
1 lime, cut into thin slices
1 to 2 teaspoons coarse sugar
Place a rack in the center of the oven and preheat the oven to 350 degrees F. Lightly mist a 12cup Bundt pan with vegetable oil spray, then dust it with flour. Shake out the excess flour and set the pan aside.
Place the cake mix, pudding mix, sugar, water, oil, 1/3 cup lime juice, ¼ cup tequila, 2 tablespoons triple sec, and the lime zest and eggs in a large mixing bowl. Beat with an electric mixer on low speed until the ingredients are combined, 30 seconds. Stop the machine and scrape down the side of the bowl with a rubber spatula. Increase the mixer speed to medium and beat for 1½ minutes longer, scraping down the side of the bowl again if needed. The batter should look smooth and thick. Pour the batter into the prepared Bundt pan, smoothing the top with the rubber spatula, and place the pan in the oven.
Bake the cake until the top springs back when lightly pressed with a finger, 42 to 47 minutes. Transfer the Bundt pan to a wire rack and let the cake cool for 10 to 15 minutes. Run a long, sharp knife around the edges of the cake, shake the pan gently, and invert the cake onto a wire rack. Let the cake cool completely, about 25 minutes longer.
Meanwhile, make the glaze: Place the confectioners’ sugar, 1 tablespoon tequila, 1 tablespoon triple sec, and 1 tablespoon lime juice in a small bowl and whisk until smooth. Slide the cake onto a serving plate. Using a long wooden skewer poke 12 to 16 holes in the top of the cake. Spoon the glaze over the top of the cake, letting it drip down the sides. Garnish the cake with the lime slices and a sprinkling of coarse sugar. Let the glaze set for 10 minutes, then slice and serve the cake.