Beat butter at medium speed with an electric mixer, gradually adding sugar and beating well. Add egg and vanilla and beat well. Combine flour, soda, salt and spices; add to butter mixture, beating well. Stir in pecans. Shape dough into two 12-inch rolls. Wrap in wax paper and chill at least two hours. Unwrap rolls and cut into ¼-inch slices and place on ungreased (or Silpat-lined) baking sheets. Bake at 350 degrees for 10 to 12 minutes. Cool slightly on baking sheets, then remove to wire racks to cool completely. Note: Dough can be frozen for several months. Slice dough while frozen and bake as directed.