Ice Box Graham Cracker Cake

 
1 can condensed milk 
juice of a lemon 
lots of graham crackers
 
1.  Add the juice of one lemon to a can of condensed milk. Leave to thicken (about 15 minutes). 

2.  Put a layer of graham cracker crumbs in a 9 x 13-inch baking pan. Alternate with a layer of condensed milk. End with a layer of graham crackers. 

3.  Chill for 6 hours before cutting. 
 
Makes 1 cake.