Beat butter at medium speed with an electric mixer until creamy; gradually add sugar, beating well. Add eggs and vanilla, beating until well blended.
Combine flour and next 3 ingredients; gradually add to butter mixture, beating at low speed until blended after each addition. Stir in pecans. Shape dough into 1 1/2-inch balls, and place on lightly greased baking sheets.
Bake at 350° for 18 to 20 minutes or until lightly browned. Cool in pan 1 minute; remove to wire racks to cool.