Patty's grandmother sifted together the flour and baking powder three times before adding them to the batter. We had good results just whisking them together. This recipe comes from Patty Pinner's cookbook Sweets (randomhouse.com).
Grease and lightly flour a 10-inch tube pan; set aside.
For cake: In a large mixing bowl, beat the brown sugar, granulated sugar, the 1 cup butter and the shortening with an electric mixer on medium speed until mixture is light and fluffy. Add eggs one at a time, beating well after each addition.
In another large bowl, whisk together the flour and baking powder. Add half the flour mixture to the butter mixture; beat on medium-low speed to combine. Repeat with milk, followed by remaining flour mixture, scraping bowl as necessary. Stir in pecans and the vanilla. Pour the batter into the prepared pan.
Bake in a 350° oven for 1 hour and 10 minutes, or until a toothpick inserted in center comes out clean. Let the cake cool in the pan on a wire rack for 15 minutes, then unmold it to cool completely.
For frosting: In a large mixing bowl, beat the cream cheese and the 1/4 cup butter with an electric mixer on medium speed. Gradually beat in the powdered sugar, followed by the vanilla and maple- flavor extract until smooth. Spread frosting over the cooled cake on a plate.