1. Preheat oven to 350 degrees F (175 degrees C). Grease a fluted tube pan (such as Bundt®).

2. Peel mango with a vegetable peeler or paring knife. Cut flesh into small pieces and squeeze pit for juice. Collect all juice from chopping and squeezing pit and reserve for glaze. Smash mango in a bowl using a potato masher or fork. Measure 1 cup smashed mango, reserving the rest for the glaze.

3. Beat 1 cup smashed mango, cake mix, eggs, water, vegetable oil, and lime zest together in a bowl using an electric mixer for 2 minutes; pour into the prepared pan.

4. Bake in the preheated oven until a toothpick inserted in the center comes out clean, 40 to 50 minutes. Cool cake in pan for 5 minutes. Invert cake onto a wire rack to cool completely.

5. Combine butter, lime juice, about 1 tablespoon reserved juice from mango, and rum together in a bowl. Stir confectioners' sugar into butter mixture until desired consistency is reached; fold smashed mango into glaze. Spoon glaze over cooled cake.

Cook's Note:

You can also puree mango in the blender or food processor.