Preheat oven to 170c / 350f. Grease and line two 8 inch sandwich tins.
In a bowl sift the flour, baking soda, cocoa powder, salt and sugars. Make a well in the centre, pour in the beer, oil and vanilla. Whisk until there are no lumps.
Pour into the prepared tins and bake for 25-30 minutes, until a cake tester comes out clean.
Once baked, let them cool for 15-20 minutes in their tins before transferring them onto a cooling rack.
To make the buttercream, cream the vegan butter and vanilla extract together in a stand mixer. Add the icing sugar in a large tbsp at a time until well mixed.
Beat in the whiskey, cocoa powder and brewed coffee. Taste and adjust quantities if needed until it tastes just like Baileys! Refrigerate for at least an hour before decorating, to make it easier to spread.
Once the cake has completely cooled (I recommend freezing it or keeping in the fridge overnight before decorating) spread the chilled frosting on top of one layer, sandwich the two layers together and then top the cake with the rest of the frosting.
Serve and enjoy! It will keep in the fridge for up to 3 days, covered.
