Add all dry ingredients to large mixing bowl – flour, baking soda, baking powder, cocoa powder, and salt. Note: sugar is not a dry ingredient.
In a separate mixing bowl, begin adding wet ingredients – staring with sugar and oil. Using a hand mixer, blend them together. Add the egg, and mix again. Add buttermilk and vanilla extract – mix again. Finally, add red food coloring, Kahlua, and vinegar - and mix again.
Pour wet ingredients into bowl with dry ingredients, then mix just until fully combined. Do not over-mix!
Spray 7-inch push pan with nonstick cooking spray. Pour batter into pan, and cover with aluminum foil.
Place 3-inch trivet into pot, along with 1 1/2 cups of water. Then place pan on top of trivet. Lock lid and cook at high pressure for 75 minutes. Once cook time is complete, allow pressure to release naturally.
Remove push pan, uncover, and let cool for at least 10 minutes before removing cake. Then, once pan is warm to touch, push out cake to a cooling rack and let cool completely before icing.
Meanwhile - Place the butter, cream cheese, and 1 mini bottle of Baileys in a mixing bowl and mix together for a few minutes, until creamy. Slowly add the powdered sugar a little bit at a time. Lastly, increase to the highest speed until whipped texture is achieved.
Frost the cakes in the style of your choice. And enjoy!