Pre-heat oven to 350 degrees and line a cupcake tin with 12 papers.
In the bowl of a stand mixer or in a large bowl with a hand mixer, cream butter and sugar together, until light and fluffy.
In a separate medium bowl, whisk together the flour, baking flour, and salt.
Slowly mix the dry ingredients into the butter and sugar, alternating with coconut milk. Add the vanilla and mix until just blended.
In another separate medium bowl, whisk the egg whites with a hand mixer or whisk until stiff peaks form.
Gently fold the egg whites into the batter, until just blended. Then fold in the shredded coconut.
In prepared cupcake tin, fill cupcake papers about ¾ of the way with batter.
Bake cupcakes for 15-17 minutes, until a toothpick inserted into the center comes out clean. Cool cupcakes in tins for a few minutes before removing to wire racks to cool completely.
Once cupcakes are completely cooled, core out the middle with a knife or cupcake corer.
Using a pastry bag with tip, pipe about a tablespoon of fresh chocolate mint buttercream into the cupcake. Then pipe frosting onto the top of the cupcake. Top with sugared mint leaves.