Step 1

Line a 9 x 5-inch loaf pan with plastic wrap, making sure there is overlap over all edges. Spread 1½ cups whipped topping into bottom of lined pan. Arrange 2½ graham cracker sheets over whipped topping, breaking crackers as needed to fit into pan.

Step 2

In a medium bowl, stir together ½ cup whipped topping, pumpkin, sugar, and 1 tsp pumpkin pie spice. Spread half of pumpkin mixture over graham cracker layer in pan. Top with 2½ graham cracker sheets, breaking crackers as needed to fit into pan. Spread remaining pumpkin mixture over graham crackers. Top with remaining 3 graham crackers, breaking crackers as needed to fit into pan. Spread remaining 1 cup whipped topping over graham crackers. Cover loosely and refrigerate at least 4 hours or up to overnight to soften graham crackers.

Step 3

Freeze cake for 1 to 1½ hours before serving to firm it up. Remove from freezer, uncover, and invert onto a platter; discard plastic wrap. Dust cake with remaining ¼ tsp pumpkin pie spice. Serve immediately.

Step 4

Serving size: 1 (1-inch-thick) slice