FOR CAKE: Position rack in center of oven and preheat oven to 350 degrees. butter and flour 12 cup bundt pan. Combine prunes, water and Armagnac in heavy medium saucepan. Simmer until prunes are tender, about 15 minutes. Drain prunes, reserving 1/4 cup cooking liquid for glaze. Coarsely chop prunes.

Beat oil, sugar, eggs and vanilla in large bowl until well blended. In medium bowl, mix flour, baking soda, spices and salt to blend. Mix dry ingredients into dry mixture. Add buttermilk, beating until batter is smooth. Fold in chopped prunes. Transfer batter to prepared pan. Bake cake until tester comes out clean, about 1 hour 5 minutes. Transfer to rack in pan.

FOR GLAZE: Combine reserved 1/4 cup prune cooking liquid, sugar, butter, Armagnac, corn syrup, lemon juice and baking soda in heavy large saucepan. Bring to boil over medium heat, stirring occasionally. Boil 2 minutes.

Pierce cake in several places with long toothpick or wooden skewer. Slowly pour 1 1/4 cups glaze over hot cake. Reserve extra glaze. Let glazed cake cool in pan 30 minutes. Turn cake out onto platter. Cool completely.

Cut cake into wedges. Serve with vanilla ice cream, passing additional glaze separately as sauce.