Combine first 4 ingredients; set aside. Beat butter at medium speed with an electric mixer until creamy; gradually add 2 cups of sugar, beating well. Add eggs 1 at a time, beating after each addition.
Combine flour, baking powder and salt; add to butter mixture alternately with sour cream, begininning and ending with flour mixture. Mix at low speed after each addition until blended. Stir in vanilla.
Pour half of batter into a well-greased and floured bundt pan. Spoon apple mixture over batter, leaving a 1/2 inch border around edges. Pour remaining batter over mixture. Bake at 350 for 50-55 minutes or until wooden pick inserted in center comes out clean. Cool in pan on wire rack for 10 minutes. Remove from pan; cool on wire rack. Drizzle with glaze. Store in refrigerator.
For glaze: Combine first 4 ingredients; beat at medium speed with an electric mixture until smooth. Gradually add sugar; beating at low speed until smooth.