1-Preheat oven to 350 °F and coat: Preheat oven to 350 °F and coat two small loaf pans with non-stick baking spray.
2-In a large mixing bowl, combine the: In a large mixing bowl, combine the cake mix, water, melted butter, egg, key lime juice, key lime zest and gel food coloring (if using).
3-Divide the batter between the two pans: Divide the batter between the two pans. Gently tap the pans on the countertop to help release any air bubbles in the batter.
4-Place the loaf pans onto a large: Place the loaf pans onto a large baking sheet and into the oven to bake for 30-35 minutes, or until a toothpick inserted in the middle of the cake comes out clean.
5-Remove from oven and place on a: Remove from oven and place on a wire rack to cool for 10 minutes before flipping the bread out of the pans.
To Make the Glaze
6-Place the cooled pound cake loaves on: Place the cooled pound cake loaves on a wire rack, with a baking sheet underneath to catch any drips.
7-In a medium bowl, whisk together the: In a medium bowl, whisk together the powdered sugar, lime juice and lime zest until combined and smooth.
8-Slowly pour the glaze over the two: Slowly pour the glaze over the two cakes.
9-Allow to set before cutting and serving: Allow to set before cutting and serving.