1. Heat oven to 325 degrees F. Grease and flour 10-cup Bundt pan.
2. Sift together flour, baking soda, salt, baking powder, cinnamon and nutmeg into large bowl.
3. Beat eggs and oil in large bowl with mixer. Add apple, sugar and vanilla; beat 1 minute on high speed.
4. Beat in flour mixture on low speed until blended. Increase speed to high; beat for 2 minutes, scraping down side of bowl occasionally. Stir in walnuts. Scrape into prepared pan.
5. Bake in 325 degrees F oven 40 minutes. Increase temperature to 350 degrees F. Bake 15 to 20 minutes, until wooden pick inserted in center comes out clean. Cool cake in pan on wire rack for 20 minutes. Invert onto serving plate.Topping:
6. Combine confectioners sugar and brown sugar in bowl. Sift with flour sifter over cake.