Rich Chocolate Truffle Fudge Cake- Justine Pattison's showstopper recipe

Ingredients

• 50 g cocoa powder
• 6-7 tbsp just-boiled water
• 225 g softened butter (cubed, plus extra for greasing)
• 225 g caster sugar
• 4 large eggs
• 225 g self-raising flour
• 1 tsp baking powder
• 350 ml double cream
• 400 g plain dark chocolate ((around 70% cocoa solids), broken into pieces)
• 12 chocolate truffles (plain, white or milk)