Preheat your oven to 180C / 350F / 160C fan forced and line a lamington tin (approx 22cm x 33cm) with baking paper.
Sift together the flour, cornflour, baking powder and salt and mix well.
Beat together the butter and sugar until very light and fluffy. Add the whole eggs and beat well until fully incorporated. Now add the egg whites and vanilla and beat until the mixture looks whipped and light. Scrape down the sides of the bowl from time to time.
Add 1/2 the flour mix and fold through gently with a spatula. Now add the milk, fold through. Add the remaining flour and fold through gently again until just combined.
Spread the batter evenly in prepared tin. Bake for 35-40 minutes, turning at the halfway mark, until the top is golden and a toothpick inserted comes out clean. Allow it to cool slightly, then turn out onto a wire rack to cool completely.
FOR THE ROSE AND STRAWBERRY GLAZE
Place the sugar and water in a saucepan and sprinkle the gelatine powder over the top. Wait for 5 minutes, then heat over low heat until the sugar and gelatine dissolve. Place the strawberries in a blender and pour the syrup over the top. Puree to a liquid.
Pour the liquid through a strainer into a pouring jug and add the rosewater essence. Sift the icing sugar into a clean bowl. Add the melted butter and pour in the strawberry syrup. Whisk until smooth then leave in the fridge for 15-30 minutes to cool and thicken slightly.
Place the coconut into a separate bowl. Set a wire rack over a large baking tray.
Cut the edges off the sponge and cut into squares, also cutting the golden edges off each square (notes).
using two forks, dip the sponge into the strawberry mixture, turning to coat each side. Let the excess drip off then immediately coat in coconut and place on the wire rack to set.
I use a standard Australian 20ml tablespoon (4 teaspoons worldwide)
For best results you should always weigh ingredients like flour and sugar. Kitchen scales like these are relatively cheap but if you can’t weigh the ingredients, use the spoon and level method (don’t scoop).
I use corn starch a lot in my baking. Cake flour is a combination of all purpose and corn starch but in Australia is not so readily available. I use this combo in my recipes a lot instead of using cake flour.
You can use a ruler to get perfect squares like it do but it is not necessary. When trimming the golden edges off, make sure to cut away as little as possible.