To serve a high cake like this, rather than trying to cut small slices and risk the chance that they might collapse, it is best to cut a regular-sized piece, then separate the slice into two servings of two layers.
Cream cheese filling
1.Make lemon curd.
2.Preheat oven to 170°C/340°F. Grease two deep 22cm (9-inch) round cake pans; line bases and sides with baking paper.
3.Beat butter, essence and caster sugar in a large bowl with an electric mixer until light and fluffy. Beat in eggs, one at a time.
Stir in coconut and sifted flour, then sour cream and milk in two batches. Divide mixture evenly between pans; smooth the surface.
4.Bake cakes for 1 hour or until a skewer inserted into the centre comes out clean; cover cakes loosely with foil if they start to over-brown. Leave cakes in pans for 5 minutes before turning, top-side up, onto a wire rack to cool.
5.Make cream cheese filling.
6.Trim tops of cakes to level, if needed. Split cakes in half. Place one cake layer on a plate or stand. Spread cake layer with a quarter of the cream cheese filling and a quarter of the lemon curd. Repeat layering with remaining cakes, filling and curd, finishing with curd. Dust with sifted icing sugar. Top with toasted coconut.
7.Finely grate rind from lemons; you will need 1 tablespoon. Squeeze juice from lemons; you will need 2/3 cup juice. Combine egg yolks, sugar and cornflour in a medium saucepan until smooth. Stir in rind and juice; stir over medium heat until sugar dissolves. Bring mixture just to the boil. Remove from heat and gradually whisk in butter until melted; strain curd into a heatproof bowl or jug. Cover surface with plastic wrap. Refrigerate until cold.
Cream cheese filling
8.Beat butter in a small bowl with an electric mixer for 3 minutes or until pale and fluffy. Add cream cheese; beat until smooth. With motor operating, gradually beat in sifted icing sugar until well combined.
Tip Save the unused egg whites to make meringues, pavlova or friands; they can be refrigerated for up to 3 days or frozen for up to 3 months.
* Do ahead Cake can be made a day ahead; keep covered in the fridge. Stand at room temperature for 30 minutes before serving.