hazelnut brown butter cake

INGREDIENTS

• 5 ounces (about one heaping cup) hazelnuts, blanched to remove dark skins*
• 1/2 pound unsalted butter (plus 1 tablespoon melted extra for greasing the pan)
• 1/2 vanilla bean
• 1 1/3 cups powdered sugar, plus extra for dusting the cake
• 1/3 cup all-purpose flour
• 5 extra-large egg whites (I used 6 since I was using
• )
• 3 tablespoons granulated sugar
• 4 ounces semisweet chocolate chips or finely-chopped chocolate
• 1/4 cup heavy cream
• 1/2 teaspoon instant coffee granules