If using the vanilla beans, spilt the pod in half and scrape out the seeds. Add the seeds (or vanilla extract) to the egg mixture and beat to combine.
Add half of the flour mixture to the egg mixtre and mix on low speed just until blended. Add the coconut milk and mix until blended. Add the remaining flour mixture and mix just until blended.
Divide the batter among the prepared muffin cups using a cookie scoop.
Bake the cupcakes for about 20 minutes or until a tester inserted into the center comes out clean. Let cool completely before frosting.
For the frosting, whisk the butter in the stand mixer until smooth. Add 2 cups of sugar, coconut milk, seeds from vanilla bean and salt. Beat on medium speed until blended. Continue to add sugar and beat on high speed until desired consistency is acheived. Add lime juice and lime rind and beat just to combine. (I added my lime juice to early which caused the butter to curdle).
Spread coconut onto a cookie sheet and toast under medium broiler until browned. Keep a close eye on the coconut as it will burn!
Since my frosting went horribly wrong, I simply used a knife to spread the frosting and then dunked the tops of the cupcakes into the toasted coconut to completely cover the frosting. Alternatively you could use a pastry bag with a large start tip to pipe the frosting onto the cupcakes and sprinkle with toasted coconut.