In a large mixing bowl, whisk together the dry ingredients: flour, baking powder, baking soda, salt, and coconut.
In another bowl, cream the butter on medium speed with an electric hand mixer for about 30 seconds. Add lime zest, sugar, vanilla, eggs.
Add the dry ingredients to the butter mixture in three parts, alternating with buttermilk and lime juice.
Bake time: Bake the cake for about 40 to 45 minutes, or until the top is domed, cracked, and golden brown.
To be sure it's done, insert a toothpick into a few places in the center, and if it comes out clean, it's ready. Allow the bread to cool before the next step.
Sugar Lime Icing: Mix the glaze ingredients in a small bowl, then drizzle the glaze over the cake. Garnish with more lime zest (optional)