In a small saucepan, whisk together cola and cocoa. Bring to a boil over medium-high heat. Remove from heat; let cool completely.
Preheat oven to 350°. Spray a 15-cup Bundt pan with baking spray with flour.
In a large bowl, beat butter and sugar with a mixer at medium speed until fluffy, 3 to 4 minutes, stopping to scrape sides of bowl. Add eggs, one at a time, beating well after each addition.
In a medium bowl, whisk together flour, baking soda, and salt. In a small bowl, stir together cooled cola mixture, buttermilk, and vanilla. With mixer on low speed, gradually add flour mixture to butter mixture alternately with cola mixture, beginning and ending with flour mixture, beating just until combined after each addition. Spread batter in prepared pan.
Bake until a wooden pick inserted near center comes out clean, 50 to 55 minutes. Let cool in pan for 20 minutes. Remove from pan, and let cool completely on a wire rack. Pour Chocolate Glaze over top of cooled cake, and let set before serving.
Recipe by Taste of the South at https://tasteofthesouthmagazine.com/chocolate-cola-pound-cake/