Line the wells of a 12 cup muffin pan with cupcake liners.
In medium bowl, sift flour, baking powder, baking soda and salt. Set aside.
In the bowl of an electric mixer fitted with the paddle attachment, beat sugar, coconut oil and cream of coconut until fluffy.
Beat in egg yolks and vanilla bean paste.
Lower the speed on your mixer, beat in dry ingredients and then buttermilk and pineapple juice, each just until blended.
Using the whisk attachment, beat egg whites with pinch of salt in another large bowl until stiff but not dry. Fold beaten egg whites into batter.
Using an ice-cream scooper, distribute the batter evenly into the cupcake liners.
Bake cupcakes for 25-30 minutes or until tester or toothpick inserted into center comes out clean.
While cakes are cooling, make the buttercream.
To make the buttercream:
Using a clean towel and some lemon juice or vinegar, clean your mixing bowl, whisk attachment to remove any traces of grease.
Fill a heavy duty pot about a quarter of the way with water and place on the stove over medium heat to simmer.
Add egg whites, sugar and salt to the mixing bowl and whisk together lightly with a hand whisk, just until combined.
Fit the bowl onto the pot, ensuring the bottom of the bowl is not in contact with the water in the pot. Whisk the sugar egg white mixture constantly, but gently, until temperature reaches 160°F.
Once at the correct temperature, remove carefully from heat, wipe the moisture away from the bottom of the bowl and transfer mixing bowl to the stand mixer. With the whisk attachment, begin to whip the meringue until it is thick, glossy, and the bottom of the bowl is no longer warm to the touch.
Do not begin adding butter while the bowl is still warm.
Switch from your whisk to paddle attachment and with mixer on low speed, add butter cubes, one at a time, until incorporated. Continue to mix until it has reached a silky smooth texture.
Add vanilla bean paste and coconut emulsion, continuing to beat on low speed until well combined.
Pipe swirls onto cupcakes and top with fresh pineapple chunks and
umbrellas for fun!
Notes
Sweet Tips: To prevent the dry ingredients from blowing out of the mixer, dampen a tea towel and drape over the mixer while mixing.
I keep two KA mixer bowls, one dedicated for meringues. If you are working with one, use lemon juice, half a lemon or white vinegar to clean your bowl and whisk attachment prior to use.