In medium bowl, stir together flour, baking soda, baking powder, salt, nutmeg, cinnamon and ginger; set aside. In large bowl, beat butter and sugar with electric mixer until light and fluffy. Add eggs, one at a time, beating well after each addition; add buttermilk and vanilla. Add flour mixture and stir until just combined. Add oats, raisins and walnuts, blending well. Drop by heaping tablespoons onto cookie sheet.