Butter and flour a Bundt pan.
 
In a large mixing bowl, combine the flour, sugars, cocoa powder, baking soda, baking powder, and salt.  Set aside.
 
In another bowl, stir together the buttermilk, eggs, oil and vanilla, and pour this into the dry ingredients. Beat with an electric mixer on a medium setting for 2 minutes.
 
Combine the Irish Cream liqueur and water and in a microwave safe bowl, heat on high for 50 seconds.  Or, warm on the stove, but do not boil.
 
Using a low speed on the electric mixer, add the liqueur mixture slowly to the chocolate batter. The batter will be quite thin.
 
Pour the batter into the prepared cake pan, and bake at 350F for 40-50 minutes.
 
Check the cake after about 45 minutes. If it's done, a toothpick inserted into the center will come out clean. If the toothpick is sticky, bake another 5 minutes, and check again.
 
When the cake is done, set the pan on a wire rack to cool for 10 minutes.
 
Place a cake plate over the top of the pan. Holding both pan and plate together (careful, it’s hot! use oven mitts) turn them over, and lift the pan off the cake.