Combine flour and sugar cut in margarine with pastry blender until mixture is crumbly
Stir in pecans
Press 1 14 cups mixture into bottom of ungreased 9-inch square pan set aside Combine remaining crumb mixture buttermilk and next 8 ingredients beat at low speed with electric mixer until blended Pour over crumb mixture and bake at 350 for 40 minutes or until a wooden toothpick inserted in center comes out clean