Preheat oven to 350 degrees Fahrenheit.

Bake four brownie bars for 10 minutes.

Pour the whipped topping into the bowl of a mixer. Beat it until stiff. Transfer the whipped topping into piping bags, or ziploc bags.

When the brownies are golden, remove them from the oven and let cool.

When cool enough to handle, press down the rim of a dessert cup into a brownie bar, to cut a piece of brownie in the shape of the cup. (Reserve the scraps.) Gently push the circular brownie bar piece toward the bottom of the cup. This will be your base.

Snip off the corner of the ziploc bag. Pipe a layer of whipped topping into the cup, on top of the brownie bar base.

Add a layer of cut brownie pieces, then another layer of whipped topping, and, finally, the remaining pieces of brownie on the top.