Preheat the oven to 350 F. Grease a 6-cup mini bundt cake pan. Set aside.

Combine the Guinness and butter in a large saucepan over medium-low heat. Once the butter has melted, remove the pan from the heat.

Whisk in the cocoa powder and granulated sugar.

In a small bowl, mix together the sour cream, eggs, and vanilla extract. Add the mixture to the Guinness mixture, whisking to combine.

Add the flour and baking soda to the mixture and whisk until smooth.

Transfer the batter to the prepared mini bundt pan.

Bake the cakes for 20 minutes or until a toothpick inserted into the center comes out clean. Let cool 10-15 minutes in the pan before inverting the pan onto a wire rack and gently removing the cakes. Let cool completely.

Beat together the powdered sugar and cream cheese until smooth.

Add the heavy cream and Bailey’s, mixing until combined.

Transfer the icing to a piping bag.

Place the green candy melts into a microwave safe bowl. Heat in the microwave, stirring every 30 seconds, until melted.

Pour the melted candy into a silicone Mickey/Minnie mold. Tap the mold on the counter a few times to reduce any air bubbles.

Place the mold in the refrigerator to set, about 15 minutes.

Pipe the icing into the center of the bundt cake and up onto the top of the cake.

Add a Mickey or Minnie candy piece to the top of the icing.