1. Prepare the Chocolate Cake

1. Preheat your oven to 350°F (175°C) and grease a 9×13-inch baking dish.
2. Prepare the chocolate cake batter according to the instructions on the box or your homemade recipe. Pour the batter into the prepared baking dish.
3. Bake the cake for 30-35 minutes, or until a toothpick inserted into the center comes out clean. Remove the cake from the oven and allow it to cool for 10-15 minutes.

2. Poke the Cake

1. Once the cake has slightly cooled, use the handle of a wooden spoon or a large straw to poke holes evenly across the surface of the cake. Be sure to poke all the way down to the bottom of the cake to allow the filling to soak in.

3. Make the Filling

1. In a small saucepan over low heat, combine the sweetened condensed milk and Irish cream liqueur. Stir constantly until the mixture is warm but not boiling.
2. Add the chocolate chips and continue stirring until the chocolate is melted and the mixture is smooth. Remove from heat.

4. Fill the Cake

1. Pour the warm chocolate and Irish cream mixture over the cake, ensuring it seeps into the holes. Use a spatula to spread it evenly across the surface.
2. Allow the cake to cool to room temperature, then cover it and refrigerate for at least 2 hours to let the filling set.

5. Make the Whipped Topping

1. In a large mixing bowl, combine the heavy cream, powdered sugar, vanilla extract, and Irish cream liqueur.
2. Use a hand mixer or stand mixer to whip the cream on medium-high speed until stiff peaks form. Be careful not to overmix.

6. Top the Cake

1. Spread the whipped cream evenly over the chilled cake.
2. Garnish with chocolate shavings, a dusting of cocoa powder, or a drizzle of Irish cream liqueur for an elegant touch.

7. Serve and Enjoy

Slice the cake into squares and serve chilled. Store any leftovers in the refrigerator for up to 3 days.