Turn out into a lined and greased 23 x 29 cm roasting or oven pan. Bake at 180°C for about 20 minutes. Cool slightly in the pan before turning out onto a wire rack to cool completely. Cut into squares or any other shapes of your choice.
For the icing, sift icing sugar. Add lemon juice and enough water and whisk to a smooth, runny consistency. Add lemon rind and colouring. Ice the top of the cake squares on a wire rack, over a tray. Re-use icing that dripped into tray.
Butter cake: Bake in two greased, 20 cm cake pans for about 25 minutes.
Jelly cakes: Omit lemon essence and lemon rind. Add 3/4 of a packet of jelly powder (flavour of your choice) to cake batter and sprinkle remaining 1/4 packet jelly powder over the icing.
Cake Pops: Use sponge and bake in silicone tray for round cake pops. Increase icing sugar to 4 cups and water to about 80 ml (1/3 cup). Makes about 6 cake pops.