Pre-heat the oven to 180ºC/160ºC fan
Line a muffin tin with 8 cupcake cases
Using an electric mixer, whisk the double cream (120ml) to stiff peaks. Once stiff, add the vanilla extract (½ tsp) and gradually add the Baileys (50ml) thoroughly mixing each addition before adding more.
In a separate bowl, whisk the egg (1 medium egg) until just frothy.
Add the egg to the whipped cream and whisk for a couple of minutes.
Gradually add the caster sugar (100g), whisk in each addition before adding more. Once all of the sugar is added whisk on a high speed for a couple of minutes.
Sift the remaining dry ingredients (120g plain flour, 1 tsp baking powder, pinch of salt) into the cream mixture and carefully fold them together until thoroughly combined.
Spoon the cake batter into the cupcakes cases, ensuring it's evenly distributed.
Bake for 18-20 minutes until a skewer inserted into the centre comes out clean.
Once baked, transfer to a wire rack to cool.
While the cakes are cooling, make the buttercream and ganache.