Preheat the oven to 160 degrees Celsius. Butter a 8 x 8 x 3 inch tin and line the bottom with baking parchment / paper. Set aside.
Measure the plain flour, baking soda and salt in a small bowl. Whisk the mixture with a wire whisk to distribute the baking soda and salt evenly.
In a small pot, measure the cocoa powder and sugar. Add in the coffee and butter. Heat the mixture on medium heat, and whisk frequently until all the butter has melted, and the cocoa powder and sugar has dissolved. Pour the cocoa-coffee into a large mixing bowl and let it rest for 10 minutes to cool down.
Stir in the Baileys. Crack in one egg into the cocoa-coffee mixture and whisk it in until it has been fully incorporated. Whisk in the second egg then whisk in the vanilla extract.
Sift in the flour mixture and whisk in gently until all the flour has been incorporated. The cake batter will be thin (very liquidy) and bubbly (because of the reaction between the baking soda and the cocoa powder). Pour the cake batter into the prepared tin. Lift up the tin and drop it on the table counter-top gently 3 to 5 times to remove excess air bubbles.
Bake the cake for 1h. Cover the top of the cake with aluminum foil and continue baking for 30 minutes until a skewer inserted into the centre of the cake come out with very little crumbs.Place the cake tin on a wire rack and let it cool completely.
Once the cake has cooled completely, crumble the cake into a large bowl.
Kahlua Cheesecake
Using an electric mixer, whip the heavy cream until soft peaks formed. Refer to this video on how to whip cream.
In another clean bowl, beat the cream cheese, sugar and Kahlua until the sugar has been incorporated and the cream cheese is light and fluffy. This takes about 3 - 5 minutes. Fold in the whipped cream with a rubber spatula. Transfer the cheesecake into a piping bag and refrigerate it until needed.
Baileys Ganache
Stove method: Place the chopped chocolate in a heat-proof bowl. Place the heavy cream in a small pot and heat over medium heat until the heavy cream comes to a simmer (small bubbles appear on the sides of the pot). Pour the hot cream onto the chocolate and let it stand for 1 minute. Stir the mixture until all the chocolate has melted and the mixture is smooth. Add in the butter and stir until all the butter has melted. Let the mixture cool at room temperature until the ganache has thickened. You can place it in the fridge to speed up the process.
Microwave method: Place the heavy cream in a microwave-safe bowl (glass or ceramic). Microwave the cream on medium for 30 seconds until the cream is hot. Add in the chopped chocolate and stir – the chocolate will start to melt. Place the bowl back into the microwave and microwave for 10 seconds. Stir the mixture and if there’s any remaining un-melted chocolate, repeat the process (do not microwave for too long at one go unless you want to burn your ganache). Once all the chocolate has melted, add in the butter and let the mixture cool and thickened.
If making the ganache a day in advance, cover and refrigerate it. Take it out of the fridge 15 – 30 minutes to let it soften.
Assembly
Press a thin layer of the crumbled Baileys Chocolate Cake onto the bottom and up the sides of the moulds.
Snip the bottom off the cheesecake piping bag and pipe a small amount of cheesecake into the centre of the moulds.
Scoop a small spoonful of Baileys Ganache. Roll it into a small ball and place it in the centre of the cheesecake. Pipe a little bit more cheesecake to cover the Ganache.
Use your hands and form a small flat round of Baileys Chocolate Cake. Place it on top of the cheesecake and press it down gently - it's okay if some of the cheesecake oozes out.
Freeze the bombs for 1 hour. Unmould the bombs, pack them into containers and freeze for another 2 hours.
They can now be kept until you need them - pack them into air-tight containers and freeze them for up to 3 months.
Chocolate Glaze
Stove method: Place the chopped chocolate in a heat-proof bowl. Place the heavy cream in a small pot and heat over medium heat until the heavy cream comes to a simmer (small bubbles appear on the sides of the pot). Pour the hot cream onto the chocolate and let it stand for 1 minute. Stir the mixture until all the chocolate has melted and the mixture is smooth. Stir in the golden syrup. Add more syrup until it's of a consistency that you like (I like the glaze to be quite runny, so I use more than double the amount of syrup). Let it cool slightly.
Microwave method: Place the heavy cream in a microwave-safe bowl (glass or ceramic). Microwave the cream on medium for 30 seconds until the cream is hot. Add in the chopped chocolate and stir – the chocolate will start to melt. Place the bowl back into the microwave and microwave for 10 seconds. Stir the mixture and if there’s any remaining un-melted chocolate, repeat the process (do not microwave for too long at one go unless you want to burn your ganache). Stir in the golden syrup. Add more syrup until it's of a consistency that you like. Let it cool slightly.
Serve
Place the frozen bombs on a wire rack. Leave them for 5 minutes to let them soften slightly. Spoon the warm chocolate glaze over the bombs generously and decorate with sprinkles, nuts, or anything you like.