Pre-heat the oven to 350ºF. Grease and line 3, 8” cake pans with parchment paper.

In a bowl, whisk together the flour, baking powder, baking soda, and salt. Set aside.

In a large bowl, or in the bowl of a stand mixer, add the butter, oil, and sugar. Beat the ingredients together for two minutes, until the mixture is fluffy and light in color. If using a stand mixer, use the paddle attachment, or you can just use a hand mixer.

Add the eggs, one at a time, mixing one egg completely until incorporated before adding the next one.

Remember to scrape the bowl in between mixing.

Add the vanilla and mix to combine.

Add one third of the buttermilk to the bowl with the batter, mix on low to combine.

Next, add one third of the dry ingredient mixture. Mix on low speed.

Add another third of the buttermilk and mix.

Follow by another third of the flour mixture, mix to combine.

Add the remaining buttermilk, and mix. Finish with the remaining flour, add it to the bowl and mix on low.

You can finish by folding with a spatula, to avoid over mixing the batter.

Divide the batter between the prepared cake pans.

Bake in the pre-heated oven for about 30 minutes, until a toothpick inserted into the cake comes off clean.

Remove the cake from the oven. After 10 minutes, flip the cake onto a cooling rack or plate. Let the cake cool down completely. If you aren’t assembling the cake on the same day, wrap the completely cooled down cake in plastic wrap, and place in the fridge, or freezer.

Place the cold mascarpone and 2½ cups of the powdered sugar to a bowl and beat for 1 minute, or until incorporated. Set aside.

In another bowl, whip the heavy cream, the remaining ½ cup of powdered sugar until stiff peaks form.

Add the heavy cream to the mascarpone/sugar mixture and mix to combine. Add the Kahlua or vanilla extract and mix.

Place in a piping bag fitted with the tip of your choice. I used a large round tip.

Mix the brewed espresso with the Kahlua liqueur, if using. Set aside.

Place the first cake layer on top of a cake plate. Brush some of the brewed espresso mixture on the cake.

Pipe dots of frosting on top of the cake. Sprinkle with cocoa powder.

Top with another cake layer. Brush the cake layer with the espresso mixture. Pipe dots of frosting on top and follow with the cocoa powder.

Top with another cake layer, brush it, and pipe the remaining frosting on top, finishing again with a dusting of cocoa powder.

Place the cake in the fridge for at least 4 hours before serving.

Store the cake in an air tight container for up to 5 days in the fridge. Let the cake sit at room temperature for about 15 minutes before serving.