Orange Walnut Cake

Directions

1. 1
   Position a rack in the center of the oven and preheat to 350°F
2. 2
   Lightly butter and flour the inside of a 12-cup fluted tube pan, tapping out the excess flour.
3. 3
   Sift the flour, baking powder, baking soda and salt into a bowl and set aside.
4. 4
   In a large bowl, using a hand-held electric mixer at high speed, beat the butter until creamy, about 1 minute.
5. 5
   Add the sugar and beat until light in color and texture, about 2 minutes.
6. 6
   One at a time, beat in the egg yolks, then the orange zest.
7. 7
   Reduce the mixer speed to low and in three additions, beat in the flour mixture, alternating with the sour cream, scraping down the sides of the bowl as needed, until the batter is smooth.
8. 8
   Stir in the walnuts.
9. 9
   In a grease-free, medium bowl, using the electric mixer with clean beaters, beat the egg whites just until stiff peaks form.
10. 10
    Do not overbeat the whites, or they will look lumpy and watery.
11. 11
    Using a rubber spatula, stir about one-fourth of the whites into the batter to lighten it.
12. 12
    Pour the remaining whites on top and fold them in until they are incorporated. Scrape the batter into the prepared pan and smooth the top.
13. 13
    Bake until a toothpick inserted in the center of the cake comes out clean, 50 to 60 minutes.
14. 14
    Cool on a wire cake rack for 10 minutes.
15. 15
    GLAZE.
16. 16
    To make the glaze, whisk the Grand Marnier, confectioners' sugar and orange juice to dissolve the sugar.
17. 17
    Brush about half of the glaze over the cake, letting it soak inches Invert the cake onto the cake rack, and place the cake rack over a cookie sheet.
18. 18
    Brush the remaining glaze over the cake.
19. 19
    Cool completely.
20. 20
    (The cake can be prepared up to 1 week ahead, wrapped tightly in plastic wrap, and stored at room temperature.).