In a large bowl, cream the butter, shortening and sugar until light and fluffy. Add egg yolks, one at a time, beating well after each. Beat in extracts. Combine flour and baking soda; add to the creamed mixture alternately with buttermilk. Stir in the coconut and pecans.
In a small bowl, beat egg whites until stiff peaks form; fold into cake batter. Pour into three greased and floured 9-in. round baking pans. Bake at 325° for 25-30 minutes or until a toothpick inserted in the center comes out clean. Cool for 10 minutes before removing from pans to wire racks to cool completely.
For filling, place apricots and boiling water in a small bowl; let stand until completely cooled. Drain, reserving 1/3 cup liquid. In a small saucepan, combine the apricots, brown sugar and reserved liquid. Cook over medium heat for 20 minutes or until thickened, stirring frequently. Remove from the heat; stir in mace. Cool completely. Place in a blender or food processor; cover and process until smooth.
For frosting, in a large bowl, cream the butter, cream cheese and confectioners' sugar. Beat in vanilla.
To assemble, place bottom cake layer on a serving plate; spread with half of the filling. Repeat layers. Top with the third cake layer; spread frosting over top and sides of cake. Garnish with pecans. Cover and store in the refrigerator.