In a 9X13 pan, place 30 crackers in the bottom in a single layer.
In a saucepan on the stove, combine butter, brown sugar and white sugar on stirring often on medium heat until it comes to a simmer, add in milk, vanilla and salt and stir until well combined. Next remove from heat and stir in graham cracker crumbs.
Pour half of the sugar mixture over the crackers, next layer with 30 more crackers and pour remaining mixture and top with remaining crackers.
Melt chocolate chips with shortening in the microwave, 30 seconds at at time, stirring each time, until pourable. Pour over the crackers and try to spread so the chocolate is even.
Refrigerate for 4-5 hours or even overnight.
Cut and enjoy.
Notes
One box of club crackers (13.7 ounce) had enough to make this recipe.