Aunt Sarah used to whip this up whenever we had a crowd coming over. It is the easiest thing in the world but everyone always asks for the secret recipe.

Ingredients

24 rectangular vanilla ice cream sandwiches (standard size, unwrapped)

12 oz frozen whipped topping, thawed (about 1 1/2 standard tubs)

3/4 cup chocolate syrup, plus extra for drizzling on top

1/4 teaspoon kosher salt (optional, to balance sweetness)

Nonstick cooking spray or a thin swipe of neutral oil for the dish 

Directions

Lightly coat a 9×13-inch glass baking dish with nonstick cooking spray or a very thin film of neutral oil. This keeps the cake from sticking while still letting it cling just enough to hold its shape.

In a medium bowl, gently fold together 8 oz (about 1 tub) of the thawed whipped topping, 1/2 cup of the chocolate syrup, and the kosher salt, if using. Stir just until mostly blended but still a little streaky; you want a soft, marbled look rather than a perfectly uniform chocolate color.

Unwrap 12 of the ice cream sandwiches and arrange them in a single snug layer in the bottom of the prepared dish. You may need to cut a sandwich in half to fill any gaps; fit them in like tiles so the base is mostly covered.

Spoon the chocolatey whipped topping mixture over the first layer of sandwiches. Use an offset spatula or the back of a spoon to spread it into an even layer, pressing gently so it settles into the gaps between the sandwiches. Don’t worry if the surface looks a bit uneven—that homemade, slightly lumpy texture is exactly what you want.

Unwrap the remaining 12 ice cream sandwiches and arrange them on top of the whipped layer, creating a second layer. Again, trim a sandwich if needed so the top is mostly covered from edge to edge.

Spread the remaining 4 oz (about half a tub) of plain whipped topping over the top layer of sandwiches. Aim for a thick, fluffy coat about 1/2 inch deep. Use the tip of your spatula or a spoon to create loose swirls and peaks so the top looks casually textured rather than perfectly smooth.

Drizzle the remaining 1/4 cup chocolate syrup over the top in a zigzag or circular pattern. Lightly drag the tip of a knife or skewer through the syrup and whipped topping to create a messy, marbled effect. The surface should look swirled and a little imperfect, with some thicker patches and some thinner ones.