Maple-Glazed Sour Cream Doughnuts with Sugared-Walnut Streusel

Ingredients

• 1 large egg white
• 1/4 cup sugar
• 1 teaspoon ground cinnamon
• 1 1/2 cups chopped walnuts (about 6 ounces)
• 3 1/2 cups all purpose flour
• 1 tablespoon baking powder
• 1 teaspoon ground cinnamon
• 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
• 2 cups powdered sugar
• 1/4 teaspoon maple extract
• 5 tablespoons (about) heavy whipping cream
• Canola oil (for deep-frying)

Instructions

1. 1

   Preheat oven to 300°F.

2. 2

   Line rimmed baking sheet with parchment paper.

3. 3

   Whisk egg white in bowl until frothy, about 1 minute.

4. 4

   Whisk in sugar and cinnamon.

5. 5

   Fold in nuts.

6. 6

   Spread mixture on prepared sheet.

7. 7

   Bake until beginning to dry, about 12 minutes.

8. 8

   Using metal spatula, stir to break up nuts.

9. 9

   Continue to bake until nuts and coating are dry and golden brown, about 10 minutes; cool on sheet.

10. 10

    Transfer streusel to work surface.

11. 11

    Chop nuts into small (rice-size) bits.

12. 12

    Transfer to shallow bowl.

13. 13

    Whisk first 5 ingredients in medium bowl to blend.

14. 14

    Using electric mixer, beat sugar and eggs in large bowl until very thick, about 3 minutes.

15. 15

    Beat in orange peel and vanilla.