In a bowl, combine all ingredients except apple and nuts; mix well. Stir in apple and nuts; pour into greased and floured Bundt® pan. Bake at 300 degrees for 45 minutes. Increase heat to 325 degrees and bake an additional 20 minutes. Cool on a wire rack for 20 minutes; turn out onto a serving plate. In a bowl, whisk together powdered sugar, milk and vanilla; drizzle over cake before serving.