Sweet Potato Waffles

Ingredients

• 1 ½ pounds sweet potatoes
• 2 cups flour ( 1 cup all-purpose, 1 cup whole wheat)
• 1 tablespoon baking powder
• ½ teaspoon salt
• 6 egg whites (2 yolks reserved)
• 1 ¼ cups milk
• ¼ cup brown sugar (firmly packed)
• ¼ cup melted butter
• 1 tablespoon grated orange zest
• 1 teaspoon ground cinnamon
• ¼ teaspoon ground cloves
• ⅛ teaspoon freshly ground nutmeg
• 1 teaspoon freshly grated ginger