Preheat your oven to 350°F (175°C) and prepare a baking dish.
In a mixing bowl, cream together butter and brown sugar until smooth. Beat in the egg, vanilla extract, and coconut extract.
In another bowl, whisk together flour, baking powder, and salt. Gradually add to the butter mixture. Stir in shredded coconut and white chocolate chips.
Spread the batter into the prepared baking dish and bake for 25 minutes or until a toothpick comes out clean.
While the bars cool, prepare the lime frosting by beating together butter, lime extract, powdered sugar, heavy cream, and lime juice until smooth. Add food coloring as desired.
Spread the frosting over the cooled bars and drizzle with melted white chocolate. Allow to set before slicing.
Notes
Store any leftovers in an airtight container. You can adjust the lime juice for more or less tartness.