Preheat oven to 180 degree C/350-375 F, 10 mins before baking. Grease deep 20cm-round cake pan; line base with baking paper. Beat butter, essence, sugar & egg in a small bowl with electric mixer until light & fluffy; this process will take 5-10 mins, depending on the type of mixer used.
Using wooden spoon, gently stir in sifted flour and milk. Make sure that there are no lumps.Spread mixture into prepared pan.
Bake cake in the preheated oven for about 30 mins. Turn cake onto wire rack then turn top-side up; brush top with extra melted butter, sprinkle with combined cinnamon & extra sugar. Serve warm with butter, if desired.
Notes
Taking care to thoroughly beat the butter, essence, sugar and egg will result in a light-as-air texture to this cake, best when eaten warm with butter (courtesy:Australian W omen's Weekly Magazine) . Though this is best eaten on the day its made, you can store this cake at room temperature in an air tight container for up to 2 days.Substitution for self raising flour - to get 1 cup self-raising flour, add 1 1/2 tsp baking powder+ 1/4 tsp salt to 1 cup all purpose flour. Substitution for caster sugar: to get 1 cup caster sugar. process 1 cup granulated sugar (usual sugar) in a food processor/mixer until fine, but don't powder it like icing sugar.