Combine butter and sugar, beating well. Add egg and pumpkin; beat well.
Dissolve soda in buttermilk; stir well. Combine 1 3/4 cups flour, baking powder, salt, and cinnamon; add to creamed mixture alternately with buttermilk mixture, beginning and ending with flour mixture. Dredge pecans in remaining 1/2 cup flour, and fold into batter.
Pour batter into 2 well - greased 8-inch round cake pans. Bake at 350° for 30 to 35 minutes or until a wooden pick inserted in center comes out clean. Cool in pans 10 minutes; remove from pans, and cool completely. Spread Spiced Whipped Cream between layers and on top of cake. Sprinkle nutmeg over top of cake, if desired.