White Chocolate Mud Cake

Name: White Chocolate Mud Cake
Prep time: 20 min
Cook time: 40 min
Total time: 1 h
Cuisine: European, American, British
Ingredients: 115g (½ cup) butter; 150g (5 oz) white chocolate; 100g (½ cup) sugar; 130ml (½ cup + 1 tbsp) milk; 1 egg (large); 1 teaspoon vanilla extract; 175g (1½ cups) spelt flour (see note 1); 1 teaspoon baking powder; 75ml (¼ cup + 1 tbsp) milk; 30g (2 tbsp) butter; 20g (2 tbsp + 1 tsp) icing/confectioners'/powdered sugar; white chocolate shavings; chocolate seashells (optional - omit, or use something else)