Step 1: Make the Hot Milk Sponge Cake
Mainly, start by warming the eggs in a bowl of warm water while prepping the other ingredients. This step ensures the eggs whip up to maximum volume later on. Preheat your oven to 350°F and prepare two 8-inch square cake pans with parchment paper, grease, and flour. Melt the butter in milk over low heat and keep it warm. Beat the eggs and sugar together until tripled in volume and pale yellow in color. Sift the dry ingredients over the egg mixture and fold gently. Add the warm milk mixture and stir until combined. Pour into the prepared pans and bake for 30–34 minutes. Allow the cakes to cool completely before moving on.

Step 2: Prepare the Raspberry Glaze
In a small dish, soften the gelatin in ¼ cup of water. Heat the remaining water and sugar in a saucepan until dissolved, then add the thawed raspberries. Strain the mixture to remove seeds, then mix in the softened gelatin. Sift the confectioners’ sugar into a bowl, pour the raspberry syrup over it, and whisk until smooth. Chill the glaze slightly to thicken it.

Step 3: Assemble the Lamingtons
Cut the cooled sponge cake into squares and freeze them briefly to firm up. Set up a dredging station with the raspberry glaze and coconut. Dip each square in the glaze, letting excess drip off, then roll in coconut. Place the coated lamingtons on a wire rack and refrigerate to set.