This is my first instructable so be nice.

The is a really simple cake to make. I've just put lots of small steps.
It doesn't take a long time to make and takes about 40 minutes to cook.
The orange flavour is subtle and not overpowering.
So let's get on with it!

Step 1: Ingredients

150g butter
1 orange
150g caster sugar
3 eggs
225g self-raising flour
60ml milk
120g icing sugar
1 1/2 tablespoon orange juice (optional)

Step 2: Preheat Oven

Preheat oven to 180C or 160C fan assisted.

Step 3: Grease Cake Tin

With some butter grease a deep 20cm round cake tin.

Step 4: Measure the Ingredients

Rind a whole orange
Measure 150g butter
Measure 2/3 cup (150g) caster sugar
Measure 1 1/2 cups (225g) self-raising flour
Measure 1/4 cup (60ml) milk
And 3 eggs

Photos below:

Step 5: Mix the Ingredients

Beat the butter, rind, caster sugar, eggs, flour and milk in a medium bowl with an electric mixer at a low speed until combined.
Then increase the speed to medium until mixture is smooth.

Step 6: Spread the Mixture Into the Tin

Once smooth, spread the mixture into the greased cake tin.
Keep the mixture even and level in the tin.

Step 7: In the Oven

Next all you have to do is put it in the oven for around 40mins depending on your oven.
Take it out a little early and put a cocktail stick in the middle.
If when you pull it out it has bits of the mixture on it its not done so put it back in for a few more minutes.
It should be done when it turns golden brown.
When you take it out of the oven, leave it to cool for about five minutes before you take it out of the tin.
When its cooled a little take it out of the tin till it completely cools.

Step 8: Making the Icing

The simplest part of this instructable.
Just sift the 3/4 cup or 120g of icing sugar into a medium size bowl.
Then add 1 1/2 tablespoons of orange juice either from a carton or from the orange you use to get the rind from.
I used the orange, you only need half the orange for 1 1/2 tablespoons.
Now just mix, if it's to thick add a little more orange juice. If it's to thin add a little more icing sugar.
Its only a thin layer of icing on this cake so it doesn't look like enough to cover the top of the cake.
Then pour it into the middle of the cake and evenly distribute.