Preheat oven to 350℉. Spray 3 8" round cake pans with non stick spray and line the bottoms with parchment paper.
In a small bowl, whisk together flour, baking powder, espresso powder and salt.
Using a whisk attachment stir together sugar and oil until combined. Add one egg at a time, whisking well after each. Whisk in milk, kahlúa and vanilla until smooth. Add dry ingredients and whisk until starting to smooth out. With mixer running on low, slowly add boiling water and continue to mix until starting to combine. Increase speed and whisk until smooth, about 1 minute.
Divide batter evenly into prepared pans, using approximately 2.5 cups of batter per pan. Tap pans lightly on counter to remove any bubbles. Bake for approximately 35 minutes or until a toothpick inserted comes out clean. Allow cakes to cool in pans for 15 minutes before removing to cooling rack.
Flatten out top of cakes if necessary using a serrated knife. Brush each cake with coffee syrup. Place one cake on cake board and/or cake plate. Spread half of the coffee ganache evenly over first cake layer. Top with 1/2" layer of frosting. Place second cake layer on top of first and repeat with ganache and frosting. Add top cake and spread a thin layer of frosting over entire cake. Allow cake to cool in fridge for 30-60 minutes. Frost as desired with remaining frosting and garnish with chocolate covered coffee beans. Can be served immediately or kept cool until ready to use.
In a small pot over medium heat, whisk together all ingredients. Bring to a full boil and cook for 2 minutes. Remove from heat and allow to cool to room temperature.
Heat cream until hot, either in the microwave or stovetop. Pour hot cream over chocolate and whisk until chocolate melts and is smooth. Stir in kahlúa. Allow to cool in fridge, stirring occasionally until starting to firm up but is still spreadable.
Beat mascarpone, powdered sugar and espresso powder until smooth. Set aside. Whip heavy cream and kahlúa until soft peaks form. Gradually add mascarpone mixture and whip until thick and smooth, being careful not to over mix. Keep chilled until ready to use.