For the cupcakes: Preheat the oven to 350 degrees F. Line a muffin pan with 15 regular-size cupcake liners.
In a medium mixing bowl, sift together the cake flour, baking powder and salt. Whisk together thoroughly.
In the bowl of an electric stand mixer with the whisk attachment, whisk the egg whites until foamy. Gradually add 1/2 cup sugar and whisk until the eggs whites form a soft meringue. Remove the egg white mixture from the mixing bowl and set aside.
Using the paddle attachment, cream together the butter and remaining 1 cup sugar. Scrape down the sides of the bowl and add the flour and coconut milk, alternating between the two, beginning and ending with the flour. Once all the flour has been added, mix until smooth. Scrape down the sides and beat in the egg white mixture until smooth.
Fill the cupcake liners two-thirds full and bake until the tops are golden brown and the cupcakes are baked through, about 25 minutes. Rotate the cupcake pans halfway through the baking process.
For the lemon curd: In a microwave-safe bowl, whisk together the sugar and eggs. Stir in the butter, lemon zest and lemon juice and mix until smooth. Microwave on high for 1 minute and stir. Repeat 5 times, or until thick.
For the buttercream: In the bowl of an electric stand mixer using the paddle attachment, cream the butter until smooth. Gradually add the powdered sugar and beat until smooth. Beat in the extracts and lemon zest and beat until light and fluffy.
For the coconut: While cupcakes are baking, spread the shredded coconut over a sheet pan and toast and until light brown, about 7 minutes.
To assemble: Once the cupcakes are cool, core out the middle of each cupcake and generously fill with the lemon curd. Fill a pastry bag equipped with desired pastry tip with coconut-lemon buttercream. Pipe the buttercream over the top of each cupcake and sprinkle with toasted coconut.
This recipe was created by a contestant during a cooking competition. It has not been tested for home use.