Triple Chocolate Roll Cake

Ingredients

• 1 ½ cups white chocolate chips
• 1 ½ cups heavy cream, divided
• 1 cup dark chocolate chips
• 4 egg yolks
• ⅓ cup firmly packed dark brown sugar
• 2 tbsp unsalted butter, melted and cooled
• 2 tbsp strongly brewed black coffee, cooled
• 1 ½ tsp vanilla extract
• ½ cup all-purpose flour
• ⅓ cup cocoa powder
• ½ tsp baking powder
• ½ tsp baking soda
• ¼ tsp salt
• 4 egg whites
• ¼ cup white sugar
• 1 tbsp cocoa powder or as needed