Divide the Bailey's Irish Pastry Cream into four equal parts.
Place 1 portion of the pastry cream on top of the caramel, and spread evenly with an offset spatula to a half-inch of the edge of the cake. Top the pastry cream with another layer of the cake and repeat with the caramel, pastry cream and cake layer three more times.
To garnish the cake, make a pattern with the remaining caramel sauce over the top layer of pastry cream. Garnish with some toasted oats (flaked oats toasted in a 350°F/177°C for 8 – 10 minutes and cooled) or cacao nibs.
Using the same recipes as above, this Irish Layered Cake can become an Irish Trifle: