MAKE THE GLAZE
Preheat the oven to 350°. Grease a 9-inch springform pan with the butter and dust with flour. In a small pitcher, combine the buttermilk and vanilla. In a medium bowl, whisk together the flour, baking powder, baking soda, salt and mace. In a large bowl, beat the sugar and oil for 1 minute. Add the eggs, 1 at a time, beating well after each addition. Beat in the flour mixture at low speed in 3 batches, alternating with the buttermilk, just until the batter is smooth.