Make sure that you have all the ingredients on the list.
By following the instructions on the package, prepare and bake the brownies in a 9 x 9-inch pan. If you wish to have thinner brownies, then go for a 9 x 13 pan.
Now take the baked brownies out of the oven. Immediately after you take the brownies out, cool them off for 10 minutes. (before you start the process of brushing them evenly with the bourbon). Place the pan of brownies on the cooling rack and keep both of them in your refrigerator.
Using a standing mixer or a whisk, cream the butter with the rum and powdered sugar. Continue mixing until the sugar is fully dissolved into the butter mixture. Make sure that the texture is creamy without any lumps.
Take the brownies out of your refrigerator. Now spread the rum icing evenly on the brownies that are cooled. Keep the brownie pan back in your refrigerator for around 30 minutes.
Melt the semisweet chocolate chips with the shortening in a double bath: keep a medium- sized pot with water on your stove, and bring it to a simmer. Pour the chocolate chips and shortening into a small saucepan and keep it on the top of the pot with hot water. Using a rubber spatula, mix it until the chips melt and they are blended well with the shortening.