01 - Preheat oven to 350°F. Grease an 8-inch square baking pan and line with parchment paper.
02 - In a medium bowl, whisk together the flour, baking powder, and salt. Set aside.
03 - In a large bowl using an electric mixer, beat the softened butter and sugar together until pale, light, and fluffy.
04 - Add eggs one at a time, beating thoroughly after each addition. Stir in the vanilla extract until evenly combined.
05 - Gradually fold the dry ingredient mixture into the butter mixture, alternating with the milk, mixing until just combined. Do not overmix.
06 - Pour the batter into the prepared pan and smooth the top evenly. Bake for 20–25 minutes or until a toothpick inserted into the center comes out clean.
07 - Let the cake cool completely in the pan, then turn out onto a wire rack. Wrap tightly and freeze for 30 minutes to firm the crumb for easier dipping.
08 - Combine raspberries, water, sugar, and lemon juice in a saucepan. Simmer over medium heat for 5–7 minutes, stirring occasionally. Strain through a fine mesh sieve to remove seeds and let cool completely.
09 - Using a serrated knife, cut the cooled sponge cake into 12 even squares.
10 - Spread desiccated coconut in a wide, shallow bowl. Dip each sponge square briefly into the cooled raspberry syrup, allowing excess to drip off, then roll gently in coconut to coat all sides evenly.
11 - For a filled version, slice each sponge square in half horizontally. Spread the bottom half with raspberry jam, pipe or spoon whipped cream on top, and sandwich with the upper half before coating in syrup and coconut.
12 - Place finished lamingtons on a wire rack and let set for 15 minutes before serving.