Begin by crushing the entire package of Oreo cookies. You can do this in a food processor until finely ground, or place them in a large zip-top bag and crush with a rolling pin. Pour the cookie crumbs into a bowl, add the melted butter, and stir until the mixture resembles wet sand.

Line a 9×5 loaf pan with plastic wrap, leaving overhang for easy removal later. Press about two-thirds of the Oreo crumb mixture into the bottom of the pan, pressing firmly to form a compact crust. Reserve the remaining crumbs for topping.

Working quickly, scoop half of the softened vanilla ice cream over the crust and spread evenly. Sprinkle in a generous layer of the chopped mini peanut butter cups (use about half). Drizzle about half of the hot fudge sauce over this layer.

Add the remaining ice cream over the fudge and peanut butter cups. Smooth the top. Sprinkle the rest of the chopped peanut butter cups on top, drizzle remaining fudge, and then top it off with the remaining Oreo crumbs for a crunchy finish.

Cover the entire pan tightly with foil or more plastic wrap. Place the loaf pan in the freezer and freeze for at least 4 hours, preferably overnight, until the dessert is solid and can be sliced.

When ready to serve, lift the loaf out of the pan using the plastic wrap. Slice with a sharp knife (you may need to let it sit for a few minutes to soften slightly), and enjoy this decadent layered frozen dessert.