Preheat oven to 160ºC Grease and flour bundt pan. Cream butter and sugar. Add cocoa and egg yolks. Dissolve soda in water and combine with coffee and kahlua; add to batter alternately with the flour. Add vanilla and fold in stiffly beaten egg whites. Pour batter in pan, remove air bubbles. Bake 1 hour. Combine glaze ingredients and pour over warm cake. Cover with foil and freeze. About 1 hour before serving, remove from freezer and ice with whip cream.