Let 1 cup of the butter and eggs stand at room temperature for 30 minutes. Meanwhile, grease and flour a 10-inch fluted tube pan; set aside. In a medium bowl stir together flour, baking powder, baking soda and salt; set aside.
Preheat oven to 325°F. In a large mixing bowl beat softened butter with an electric mixer on medium to high speed for 30 seconds. Gradually add 2 cups sugar, about ¼ cup at a time, beating on medium speed until well combined. Scrape sides of bowl; beat for 2 minutes more. Add eggs one at a time, beating well after each addition. Beat in 1 Tbsp. vanilla. Alternately add flour mixture and buttermilk to butter mixture, beating on low speed after each addition just until combined. Spread batter in the prepared pan.
Bake 60 to 70 minutes or until a wooden toothpick inserted near the center comes out clean.
During the last 20 minutes of baking, prepare Butter Sauce. In a medium saucepan combine ¾ cup sugar, ⅓ cup butter, water and 1 Tbsp. vanilla. Cook and stir over medium heat until sugar is dissolved and butter is melted. Do not boil.
When cake is done, generously prick holes in warm cake using a 8- to 10-inch skewer. Gradually spoon Butter Sauce over cake. Let cake cool in pan 30 minutes. Loosen edges of cake from the pan. Remove cake from pan and serve warm.
