Prepare Ingredients: Start by ensuring your butter, eggs, and coconut milk are at room temperature for optimal mixing. Preheat your oven to 175°C (fan). Gather your ingredients in one area to have everything at your fingertips.

Make Coconut Sponge: In a mixing bowl, cream together 200g of softened unsalted butter and 225g of caster sugar until light and fluffy, about 3-5 minutes. Add the three large eggs one at a time, mixing well after each addition. Sift in the 180g of plain flour, 2 tsp of baking powder, and 30g of cornflour, then stir in 2 tsp of vanilla essence and 120ml of coconut milk until just combined.

Bake: Pour the coconut sponge batter into a greased and lined 8x8 inch baking tin, spreading it evenly. Bake in your preheated oven for approximately 30 minutes, or until a toothpick inserted in the center comes out clean. Allow the sponge to cool completely in the tin, then gently transfer it to a cooling rack before trimming and slicing it into 16 squares.

Prepare Passionfruit Curd: While the sponge cools, prepare the passionfruit curd. Sift the 125g of passionfruit pulp to remove seeds. In a saucepan, combine the pulp, 100g of unsalted butter, and 125g of caster sugar over medium heat until melted. Gradually whisk in 2 lightly beaten eggs and 1 tsp of cornflour, cooking gently until the mixture thickens, about 5-7 minutes. Once thick, transfer the curd to a bowl and cool completely.

Make Buttercream: For the buttercream, beat 200g of softened unsalted butter and 400g of icing sugar in a mixing bowl until light and fluffy, about 4-5 minutes. Add in 1 tbsp of coconut milk and mix until well incorporated. Transfer this smooth mixture into a piping bag, ready for filling the lamingtons.

Make Passionfruit Icing: Sift 50g of passionfruit curd to remove any seeds and combine it with 300g of icing sugar in a bowl. Gradually add 4-5 tbsp of water, mixing until you achieve a smooth, drizzling consistency.

Assemble Lamingtons: Cut each sponge square in half horizontally to create layers. Pipe the buttercream around the edges of the bottom half, creating a small barrier. Spoon a layer of the passionfruit curd inside and carefully place the top half of the sponge back on to sandwich the two layers together. Repeat for all squares.

Coat: Crumb coat each assembled lamington with a thin layer of leftover buttercream to seal in the layers, then chill them in the fridge for about 30 minutes until firm. Dip each lamington in the passionfruit icing, allowing the excess to drip off. Roll in 150g of desiccated coconut to finish, then top with remaining buttercream and a drizzle of curd for extra flair.