1. Set oven at 325 degrees. Grease and flour a 9-by-13-inch pan.
2. In a medium bowl, whisk together the flour, baking soda, baking powder, salt, cinnamon, nutmeg, and allspice or apple pie spice; set aside. 3. Using an electric mixer in a large mixing bowl, cream the butter with the brown and granulated sugars until light and fluffy. Beat in the eggs, one at a time, stopping between each addition to scrape the sides and bottom of the mixing bowl. Beat in vanilla and cider or apple juice.
4. With the mixer set on low speed, beat in the flour mixture until evenly moistened. With a rubber spatula, fold in the apples and walnuts.
5. Spread the batter in the prepared pan. Transfer to the oven and bake for 45 minutes or until a cake tester inserted in the center comes out clean.
6. Remove the cake from the oven and set on a wire rack to cool completely.
FROSTING
| | 5 tablespoons unsalted butter 1/2 cup firmly packed brown sugar 1/4 teaspoon salt 3 tablespoons milk 1 1/2 cups confectioners' sugar 1/2 teaspoon vanilla extract 1. In a small pan over medium heat, melt the butter. Stir in brown sugar and salt. Cook, stirring, until the sugar melts. Add the milk, bring to a boil, and pour into a mixing bowl. Cool for 10 minutes.
2. Stir in confectioners' sugar and vanilla. Beat well; if the mixture seems too thin, add more confectioners' sugar. Use the frosting while it is still warm.
Adapted from the upcoming``King Arthur Flour Whole GrainBaking"