1. To toast the coconut, preheat the oven to 400°F (204°C).
2. Spread the coconut out over a cookie sheet lined with parchment paper. Toast it in the oven until lightly browned, tossing occasionally. It should take a total of about 7-10 minutes.
3. Remove the coconut from the oven and set aside to cool.
4. To make the cupcakes, turn the oven down to 350°F (176°C) and prepare a cupcake pan with cupcake liners.
5. Beat the butter and sugar until light in color and fluffy, about 3-4 minutes.
6. Add the sour cream and coconut extract and mix until well combined.
7. Add the egg whites in two batches, mixing until well combined.
8. Combine dry ingredients in another bowl, then combine milk and water in another bowl.
9. Add half of the dry ingredients to the batter and mix until well combined. Add the milk mixture and mix until well combined. Add remaining dry ingredients and mix until well combined.
10. Fill cupcake liners about halfway. Bake for 15-17 minutes, or until a toothpick inserted comes out with a few crumbs.
11. Remove cupcakes from oven and allow to cool for 2-3 minutes, then remove to cooling rack to finish cooling.
12. While cupcakes cool, make the frosting. To make the meringue, combine the sugar, cream of tartar, coconut extract and egg whites in a large mixer bowl. Place the bowl over a saucepan or pot of simmering water. You can also use a double boiler.
14. Whisk constantly until sugar is dissolved and whites are warm, to 160 degrees on a thermometer, about 4-6 minutes. Remove from heat.
15. Using the whisk attachment, beat the egg white mixture on low speed, gradually increasing to high, until stiff, glossy peaks form, 5 to 7 minutes.
16. Fold 3 cups of the toasted coconut into the meringue. Set aside.
17. Put the chocolate chips for the ganache in a medium heat proof bowl.
18. Heat the heavy whipping cream until it begins to boil, then pour it over the chocolate chips.
19. Allow the chocolate and cream to sit for 3-5 minutes, then whisk until smooth.
20. Spread a small amount of chocolate ganache over the tops of each cupcake.
21. Pipe the frosting onto the top of the cupcakes in a mound. I used Ateco tip 808. You can use an offset spatula to help shape the frosting into a mound, if needed.
22. Use the remaining cup of coconut to sprinkle over and around the frosting.
23. Refrigerate cupcakes until ready to serve. Serve at room temperature. Cupcakes are best for 2-3 days.