Meet the ultimate picnic dessert: S'mores Icebox Cake! This easy make-ahead dessert is quick to throw together with just a few ingredients and the results are beyond delicious.
In a large bowl, use a mixer to mix the pudding and the milk until it thickens to a soft set, about two minutes. Set aside.
Place 3 Tablespoons whipped topping into the 8" x 8" pan and use an offset spatula to spread it into an even layer on the bottom of the pan.
Line three graham crackers next to each other and then 1 and ½ graham crackers in the remaining space (the idea is to make a single layer, but its ok if they overlap a bit. You can gently press them down with your hands to make them a bit more even.
Take ½ cup of pudding and gently spread it into a single layer on top of the graham crackers.
Add another layer of graham crackers on top of the pudding.
Spread ½ cup whipped topping evenly onto the graham crackers.
Add another layer of graham crackers on top of the whipped topping.
Spread ½ cup pudding evenly onto the graham crackers.
Add another layer of graham crackers on top of the pudding.
Spread ½ cup whipped topping evenly onto the graham crackers.
Add another layer of graham crackers on top of the whipped topping.
Spread remaining pudding in an even layer on top of the graham crackers.
Spread marshmallows in an even layer over the top of the pudding and gently press in.
Cover and chill for 3 hours or more (the longer it chills, the softer the graham crackers will get).
(Optional) before serving place the oven rack at the second highest place and broil the marshmallows on top of the cake for 2-3 minutes watching carefully until golden brown. Serve immediately.