Chocolate Orange Cake

Name: Chocolate Orange Cake
Prep time: 45 min
Cook time: 35 min
Total time: 1 h 20 min
Yield: 12
Ingredients: 6 Eggs, large; 350 g Butter or baking spread, unsalted; 1/2 tsp Baking powder; 350 g Caster sugar; 100 g Cocoa powder; 450 g Icing sugar; 4 tsp Orange extract; 300 g Self raising flour; 1 Terry's chocolate, Orange; 250 g Butter, unsalted; 3 tbsp Milk; Orange sprinkles (optional)