Yield: 60 biscotti Ingredients 1/4 cup The Perfect Purée Lemon Zest,  thawed 1 1/4 cups unsalted butter, softened 3 2/3 cups sugar 5 eggs 5 1/2 cups all-purpose flour 2 tsp. baking powder 1/2 tsp. salt 1 egg, beaten sanding or sparkling sugar, if desired Procedure: Preheat oven to 350 degrees. Cream together the butter…