Preheat the oven to 350 degreed F and line three six-inch cake pans with parchment paper and grease the sides.

In the bowl of a stand mixer fitted with a paddle attachment, sift the flour, sugar, baking powder, baking soda and salt.

In a separate bowl, prepare the wet ingredients by beating together the yogurt, coconut milk, pureed pineapple, vanilla extract , and coconut extract. (To puree the pineapple pieces, simply pulse in a blender)

Add the butter in chunks to the flour mixture and mix on low speed until it resembles wet sand.

Add half of the wet ingredients to the flour butter mixture, and mix until mostly combined. Scrape down the bowl, then add the remaining wet ingredients and mix until just combined.

In a separate bowl, beat the egg whites to soft peaks. Gently fold the egg whites into the cake batter until just combined.  

Pour the batter evenly between the three pans and bake for 30-35 minutes or until the top of the cake springs back when you touch it.

After cooling for 15 minutes or so, turn the cakes out of the pans, and allow to cool completely on a cooling rack.

In a double boiler, heat the egg whites, sugar, and salt, whisking frequently until it reaches 160 degrees F or until the sugar is completely dissolved and the egg whites do not feel grainy.

Transfer the egg white mixture into a bowl of a stand mixer with a whisk attachment. Whisk on high speed until stiff peaks form.

Cut the butter into cubes and add to the meringue one piece at a time, allowing each piece to fully incorporate before adding the next. Once all of the butter is added, it will likely look curdled, but keep beating for a few more minutes and it will come together.

Once the buttercream has mostly come together, change the whisk attachment to the paddle and keep mixing on low speed until homogenous and smooth. Add the coconut extract until fully combined. If there are still tiny pieces of butter, keep beating on low speed. Do not increase the speed too high or you will incorporate too much air into the buttercream and it will not spread smooth on the cake. 

Secure the first layer of cake on the cake stand with a small amount of frosting on the bottom. Use a cookie or ice cream scoop to measure out the frosting for each layer. I used a 3 tablespoon cookie scoop and put 3 scoops of frosting on each layer. Cover the whole cake in a thin layer of frosting for the crumb coat. Place in the fridge to firm up for one hour. 

While the cake chills, prepare the coconut decoration. Place 50g (half) of the shredded coconut in a small frying pan over low heat and toast until golden. Mix the toasted coconut with the non-toasted coconut and set aside. 

After one hour, frost the cake with a thicker layer of frosting, making it as smooth as possible. With your hand, press the toasted coconut mixture all over the cake. 

Top the cake with the top of a pineapple if desired.