Prepare the Cake Pans:

1. Preheat your oven to 350°F (175°C). Grease three 8-inch or 9-inch round cake pans with butter or baking spray, then line the bottoms with parchment paper circles. Grease the parchment paper as well. This double-insurance method ensures your cakes will release perfectly.

Mix the Dry Ingredients: 2. In a large mixing bowl, whisk together the flour, sugar, cocoa powder, baking soda, baking powder, salt, and instant coffee powder. Whisk for at least 30 seconds to ensure everything is evenly distributed and there are no cocoa clumps.

Combine the Wet Ingredients: 3. In a separate medium bowl, whisk together the buttermilk, vegetable oil, eggs, vanilla extract, and Irish cream liqueur until smooth and well combined.

Make the Batter: 4. Pour the wet ingredients into the dry ingredients and mix with a rubber spatula or on low speed with an electric mixer until just combined. Don’t overmix at this stage.

5. Carefully stir in the hot water. The batter will be quite thin – this is normal and creates the incredibly moist texture! Mix until the water is fully incorporated and the batter is smooth.

Bake the Cakes: 6. Divide the batter evenly among the three prepared pans. I recommend using a kitchen scale for perfect accuracy, but eyeballing works too – each pan should be about two-thirds full.

7. Bake for 23-27 minutes, or until a toothpick inserted into the center comes out with just a few moist crumbs (not wet batter). The tops should spring back lightly when touched. For 8-inch pans, bake closer to 27 minutes; for 9-inch pans, check at 23 minutes.
8. Remove from the oven and let the cakes cool in the pans for 15 minutes on cooling racks. Then carefully turn them out onto the racks, peel off the parchment paper, and let them cool completely before frosting – this takes about 1-2 hours. Don’t rush this step!

Make the Irish Cream Buttercream: 9. In a large bowl with an electric mixer, beat the softened butter on medium speed for 3-4 minutes until light, fluffy, and nearly white in color. This step is crucial for silky frosting.

10. Add 3 cups of powdered sugar, one cup at a time, beating on low speed after each addition. Scrape down the sides of the bowl as needed.
11. Add the Irish cream, heavy cream, vanilla, and salt. Beat on low speed until combined, then increase to medium-high and beat for 2-3 minutes until fluffy.
12. Add the remaining powdered sugar one cup at a time, beating well after each addition. Add enough sugar to reach your desired consistency – the frosting should be spreadable but hold its shape. If it’s too thick, add a tablespoon more of cream; if too thin, add more powdered sugar.

Assemble the Cake: 13. If your cake layers have domed tops, use a serrated knife or cake leveler to trim them flat. This creates clean, professional-looking layers.

14. Place the first cake layer on your serving plate or cake stand. Spread about 1 cup of buttercream evenly over the top, leaving a small border around the edge.
15. Add the second cake layer and repeat with another cup of buttercream.
16. Place the final cake layer on top. Use the remaining buttercream to frost the top and sides of the entire cake. For a smooth finish, try the “crumb coat” technique: apply a thin layer first to seal in crumbs, refrigerate for 20 minutes, then apply a final smooth layer.

Make the Chocolate Ganache: 17. Place the chocolate chips in a heat-safe bowl. In a small saucepan, heat the heavy cream until it just begins to simmer (don’t let it boil).

18. Pour the hot cream over the chocolate chips and let sit for 2 minutes without stirring. Then stir gently until completely smooth and glossy.
19. Stir in the Irish cream liqueur if using. Let the ganache cool for about 10 minutes until it’s slightly thickened but still pourable.
20. Pour the ganache over the top center of the cake, using an offset spatula to gently encourage it to drip down the sides in an attractive pattern. You can cover the top completely or leave some buttercream showing – either looks beautiful!

Chill and Serve: 21. Refrigerate the cake for at least 30 minutes to set the ganache and firm up the frosting before slicing. Remove from the fridge 20-30 minutes before serving for the best texture and flavor.