Best Ever Easy Sponge Cake

Why I Love This Recipe
this comes from a stephanie alexander recipie, with a few small changes of my own.
Ingredients You'll Need
5 eggs at room temperature (very important!!)
3/4 cup castor sugar
150g plain flour
50g butter, melted and cooled
1 tsp vanilla
Directions
preheat oven to 180degreesC and grease well and line the bottom of a circular cake tin (deep).
using an electric mixer with a large bowl, beat the eggs, sugar and vanilla until thick like mousse (about 10 mins).
sift the flour into the egg mix then gently but thouroughly mix the flour through.
trickle the melted butter down the sides of the bowl then combine gently but thouroughly.
bake for 12-15mins until the top is springy. do not open the oven until at least 12mins have elapsed.
allow to cool slightly in tin before turning out onto a clean tea towel.
when completely cold, cut in half with a sharp bread knife. cover one half with whipped cream (i mix castor sugar and vanilla into my cream to taste) ten sandwich the other half on top.
dust with icing sugar to serve