New York chocolate brownie

Ingredients

• 200 gram butter
• 430 gram raw or brown sugar
• 1/3 cup good-quality cocoa, plus extra for dusting
• 200 gram dark chocolate, chopped
• 4 eggs
• 1/4 cup water
• 100 gram flour
• 1 1/4 teaspoon baking powder
• 1/2 cup walnut halves
• 1 teaspoon vanilla extract
• icing sugar, for dusting
• Cream cheese filling
• 150 gram cream cheese, room temperature
• 3 tablespoon raw sugar
• 1 egg
• 2 teaspoon vanilla extract