The brownie layers can be made up to 2 days before assembling. finishing touches.
Garnish the sandwiches: Put your chosen garnish (see list below) in a small shallow bowl. Working with one sandwich at a time and keeping the others frozen, press some of the garnish onto some or all of the sides of the sandwich and return to the freezer. Some garnish ideas finely crushed peppermint candies, finely chopped or grated bittersweet chocolate, minced crystallized ginger, finely chopped toasted pecans, crushed toffee chips, toasted sweetened coconut flakes, and crushed amaretti cookies.
- Use a cake pan: I’ve called for using two 9-inch springform pans because it’s the easiest way to bake and assemble these brownies. But if you don’t have two of them and you don’t want to buy more than one, you can substitute a 9-inch cake pan lined with parchment for one of the springforms and proceed as directed. Assemble in the springform, not the cake pan.
- Use other flavors: Feel free to use any flavor store-bought ice cream or about 3 cups homemade ice cream or sorbet.