Generously grease 12-cup Bundt® pan. In large bowl, combine 2 1/2 cups of the flour, cocoa, sugar, salt, baking soda and yeast; mix well. In small saucepan, heat buttermilk and butter until very warm (120 to 130°F.). Add warm liquid and eggs to flour mixture; beat at low speed until moistened. Beat 3 minutes at high speed.