Nigella's Flourless Chocolate Orange Cake

Ingredients (10)

• 2 oranges
• 6 large eggs
• 1 heaping teaspoon baking powder
• ½ teaspoon baking soda
• 1 ¼ cups granulated sugar
• 2 cups finely ground hazelnuts, or store bought hazelnut meal (can substitute almond meal as well)
• ½ cup unsweetened cocoa powder
• ½ tsp ground cinnamon, optional
• Pinch salt
• Powdered sugar, optional