Bake the Cupcakes

1. Preheat your oven to 180°C (350°F) and grease a 12-cup silicone or metal muffin tray.
2. Double-sift the flour and cornstarch into a large bowl, then whisk in the sugar, baking powder, and salt.
3. In a separate bowl, whisk the eggs until light and frothy.
4. Make a well in the center of the dry ingredients. Pour in the melted butter, frothy eggs, buttermilk, and vanilla. Gently fold with a spatula just until the flour disappears—do not overmix.
5. Fill the muffin cups three-quarters full. Bake for 11 minutes, rotate the pan, and bake for another 11 to 13 minutes until the tops spring back when touched.
6. Cool in the tin for 10 minutes, then move to a wire rack to cool completely. They must be cold before the next step.

Glaze and Coat

1. Whisk the shredded and desiccated coconuts together in a shallow dish.
2. In a separate bowl, sift the powdered sugar and cocoa powder together.
3. Heat the milk and 15g of butter in a small saucepan until melted and steaming. Pour into the cocoa mixture and whisk into a smooth, glossy glaze.
4. Peel the wrappers off your cold cupcakes. Using two forks, submerge each cake entirely into the warm chocolate glaze.
5. Let the excess drip off, then roll the cake firmly in the coconut mixture. Place back on the rack and chill in the fridge for 30 minutes to set.

Fill and Frost

1. Use a cupcake corer or knife to cut a cylinder out of the center of each chilled cupcake, going halfway down.
2. Drop 1 teaspoon of raspberry jam into the well. Slice the removed cake plug in half horizontally to make a flat lid, and press it back over the jam.
3. Beat the 226g of softened butter on medium speed for a full 6 to 7 minutes until pale and incredibly fluffy.
4. Lower the mixer speed and slowly add the powdered sugar one spoonful at a time. Add the vanilla, salt, and heavy cream, then whip on medium-high for another 5 minutes until it looks like marshmallow fluff.
5. Pipe large, beautiful swirls over the jam-sealed cupcakes.