- Preheat your oven to 350ºF and line two 9-inch square baking pans with aluminum foil, leaving some overhang over at least two of the edges. Spray each with a little non-stick cooking spray and set aside.
- In a mixing bowl, beat together the melted butter and sugar for about a minute until well combined then beat in the egg and vanilla. Sift the flour, cocoa powder, and kosher salt into the bowl and stir well to combine. The batter will be almost like the consistency of a brownie.
- Divide the batter equally between the two pans and spread it into a thin layer that covers the entire base of the pan.
- Bake the cakey cookies in your preheated oven for 8–12 minutes or until the edges start to pull away from the sides and the centre of the cookies are cooked and slightly dull. Remove the cookies from the oven and allow them to cool to room temperature. Pop them in the freezer for about 30 minutes to firm up.
- When you’re ready to fill the sandwiches, remove one of the cookies along with the foil from its pan and set aside. Top the other cookie with the ice cream and gently spread it into an even layer so that it reaches the sides of the pan. Carefully remove the foil from the other cookie and lay it on top of the ice cream layer.
- Cover the pan with some plastic wrap or aluminum foil and pop it in the freezer for a couple of hours to firm up.
- When ready to serve, lift the ice cream sandwich out of the pan using the aluminum foil to help and place it on a cutting board. Using a large knife, cut the sandwich into eight smaller sandwiches and enjoy!
*Four cups of ice cream is equal to two regular sized pints of the fancy stuff