Preheat oven to 350°F (175°C).

Beat softened butter with an electric mixer until creamy.

Gradually add sugar and beat until blended.

Add eggs and vanilla extract, beating at low speed until blended.

In a small bowl, stir together cola, buttermilk, and bourbon.

In a separate bowl, combine flour, cocoa, baking soda, and salt.

Alternately add the flour mixture and cola mixture to the butter mixture, beginning and ending with the flour mixture.

Beat at low speed just until blended after each addition, scraping the bowl as needed.

Pour batter into 3 lightly greased 12-cup Bundt brownie pans, filling each three-fourths full.

Bake for 12 to 15 minutes, or until a wooden pick inserted in the center comes out clean.

Cool in pan on a wire rack for 10 minutes.

Remove from pans to wire racks and cool for 30 minutes.

Drizzle warm Bourbon-and-Cola Glaze over cakes.