Place enough graham crackers on the bottom of the cake pan to cover to make the first layer.
Prepare pudding as per package directions: In a saucepan ontop of the stove, add 2 cups of milk to pudding mix & bring to a full boil, stirring contantly. (Make 1 package of pudding at a time.)
Pour this cooked pudding over the layer of graham crackers in the cake pan. Spreading evenly with a spatula.
Repeat steps 1 - 2 - 3 until the cake pan is full to the top, (About 3 to 4 layers, ending with pudding as the top layer) Then crumble some graham crackers to make crumbs to add to the top pudding layer, as much or as little that you want. Cover with plastic wrap and refrigerate for at least 1/2 hour to an hour for pudding to set. Cut into squares and serve plain or with whipped cream/cool whip.