Prepare 6 small (4 inch) cake pans (or 2 regular, 8 inch cake pans) by lining the bottoms with baking paper (parchment paper). Do not spray sides.
In a large bowl, using a hand mixer, whack together eggs and sugar for 5 minutes. Add slowly vegetable oil and mix until fully incorporated. On low speed, begin adding flour, 1/2 cup at one time alternating with buttermilk, rum and coconut cream.
Repeat until all the ingredients are added, including baking powder. Scrape well the sides, making sure there are no lumps.
Divide batter evenly between 6 mini cake pans (or between the 2 regular size cake pans) and bake for 25 minutes. If you are using 2 regular cake pans, bake for 50 minutes.
The cakes should be a golden brown and a skewer inserted in the middle should come clean. Cool completely in the pans before removing them.
Cut each mini cake, horizontally to create 3 layers. Place bottom layer onto a plate, top with mixture of crushed pineapple and lime curd, trying to spread it evenly.
Place the second layer and add some more pineapple lime filling.
Place the top layer and press a little bit the whole cake stack.
Using a spatula, spread a thin layer of pineapple buttercream over the sides, edges and top of each cake.
Place the cakes in the fridge for at least 1 hour to set.
Once the cakes are set, spread another generous pineapple buttercream layer over the entire cake. Repeat for all mini cakes.
Coat cakes in coconut flakes, pressing lightly to set.
Refrigerate to set completely. Allow 1 hour at room temperature before serving it.