Marbled chocolate and orange loaf

The first time I tried this cake, I immediately fell in love with it. I have baked this cake about 10 times, but I never get bored of it. For me this cake represents the the perfect balance of not only flavours (I mean, chocolate and orange are amazing together) but also texture. This cake will be gone before you know it!

Ingredients:

1. 50 g plain dark chocolate (broken into squares)
2. 125 g butter, softened
3. 125 g caster sugar
4. zest of 1 orange
5. 2 eggs (beaten)
6. 125 g self-raising flour
7. 2 tsp orange juice
8. 1 tbsp cocoa power

Method:

1. Preheat oven to 180 degrees. Lightly oil a 450 g loaf tin and line with a layer of baking paper. 
2. Put the chocolate in a bowl over a saucepan of very hot water. Stir until melted. Leave to cool. 
3. Cream together butter, sugar and orange zest until pale and fluffy. Gradually add the beaten eggs, beating well after each addition. 
4. Sift in the flour, add the orange juice and fold with a spoon. Divide mixture by half into 2 separate bowls. Gently fold the cocoa powder and chocolate into one half of the mixture.
5. Drop spoonfuls of each cake mixture into prepared tin. Briefly swirl the colours together to give a marbled effect.
6. Bake in preheated oven for 40 minutes.
7. Let it cool for a few minutes and dust with icing sugar!