Cream butter; add sugar, beating well. Add eggs, one at a time, beating well after each addition. Combine next 3 ingredients; add to creamed mixture, beating well.
Dissolve soda in buttermilk, stirring well. Combine flour and salt; add to creamed mixture alternately with buttermilk mixture, beginning and ending with flour mixture.
Pour batter into 2 greased and floured 8-inch round cake pans. Bake at 325° for 35 minutes or until a wooden pick inserted in center comes out clean. Cool layers in pans 10 minutes; remove layers from pans, and let cool completely.
Spread Toasted Pecan Topping between layers and on top of cake.