Walnut Torte

Ingredients

• large eggs, separated
• sugar
• finely ground walnuts, more for garnish
• cake flour
• tablespoon baking powder
• tablespoon lemon zest
• large egg yolks
• confectioners' sugar
• milk
• ounces German sweet chocolate, melted and cooled
• teaspoon pure vanilla extract
• unsalted butter, softened
• Chocolate curls
• Coarsely chopped walnuts