Method

• 1. Pre-heat oven to 190°C (375°F / Gas Mark 5).
  
  2. Mix the butter & caster sugar together.
  
  3. In a separate bowl mix the flour, cocoa power & baking powder.
  
  4. Break an egg into the butter & caster sugar mix & stir until smooth. Put in a few heaped teaspoons of flour & again mix well. Repeat until all eggs & flour mix is used.
  
  5. Put mixture into a baking tin & bake for 40 mins.
  
  Icing
  
  6. Melt the chocolate in a bowl set over simmering water.
  
  7. Stir in the icing sugar & the butter & continue stirring until the butter has melted & the mixture is smooth.
  
  8. Remove from the heat & add the water, 1 tbsp at a time. Use while lukewarm.