Preheat oven to 350 degrees Fahrenheit, line a 9?x13? cake pan with foil, allowing it to come over the edges, then coat foil with nonstick cooking spray.

For the brownies, in a large microwave-safe bowl, melt butter and chocolate chips together in 30 second increments, stirring between. Stir mixture until smooth. Quickly whisk in (by hand) brown sugar, white sugar, vanilla, eggs, and milk, just until incorporated (don’t over-mix or brownies will be tough and lose their nice texture).

In a separate bowl, stir together flour, baking cocoa, baking powder, salt and corn starch. Add to chocolate mixture and stir just until incorporated (again, don’t over-mix!). Pour and spread mixture into prepared pan and bake for approximately 16 minutes, or just until a toothpick comes out mostly clean, with a few moist crumbs on it. You don’t want the toothpick to come out super gooey or completely clean, but moist crumbs are what you’re shooting for. Don’t over bake or they’ll lose their fudgy texture.

Let brownies cool in pan on a cooling rack for 20 minutes, then place in the fridge for a few hours to allow them to get firm and dense.

Cut the pan of brownies in half so you'll have two large pieces of brownie to make a large sandwich with.

Allow the Edwards pie to thaw, chop it into pieces, then spread, as best you can, it across one brownie section. Place the remaining brownie section on top and gently press down.

Wrap it in foil and freeze for about three hours, or until the filling has firmed up. Use a sharp knife to carefully slice it into sandwich sections.

Press graham cracker pieces onto the sides of each sandwich and serve immediately or keep in the freezer, covered, until ready to serve.