maple-glazed sour cream doughnuts with sugared-walnut streusel on BakeSpace.com

Ingredients

• Streusel
• 1 large egg white
• 1/4 cup sugar
• 1 teaspoon ground cinnamon
• 1 1/2 cups chopped walnuts (about 6 ounces)
• Doughnuts
• 3 1/2 cups all purpose flour
• 1 tablespoon baking powder
• 1 teaspoon salt
• 1/2 teaspoon baking soda
• 1 cup sugar
• 2 large eggs
• 2 teaspoons (packed) finely grated orange peel
• 1/2 teaspoon vanilla extract
• 1/3 cup melted unsalted butter, cooled briefly
• 1 cup sour cream
• Glaze
• 2 cups powdered sugar
• 1/4 teaspoon maple extract
• 5 tablespoons (about) heavy whipping cream