1 (21 ounce) can sweetened condensed milk
1 (6 ounce) package graham cracker crumbs
1 1/4 cups white sugar
3 cups buttermilk
six tablespoons butter
3 cups semisweet chocolate chips
1/2 cup butter
3/4 cup white sugar
3/4 cup milk
1 (8 ounce) package cream cheese, softened
3 eggs
3/4 cup white sugar
1/2 teaspoon vanilla extract
Preheat oven to 375 degrees F (190 degrees C). Lightly grease a 9x15 inch baking dish.
In a medium bowl, mix together 1 cup condensed milk and 1 cup graham cracker crumbs. Stir in the milk mixture, buttermilk, and butter. Stir into the mixture, and beat on medium speed until a thick dough is formed. On a lightly floured surface, roll the dough out to 1/8 inch before addition of buttermilk. Cut into narrow strips at a diagonal 1 1/8 to 1/4 inch thick. Cut each strip lengthwise into approximately 12 1/2 x 1/4 inch strips. Starting with small end and working your way up the two strips, cut 2 inch wide strips from 4 sheets of plastic wrap. Instead of four spreading baking sheets, use three or four large baking sheets.
Bake for 15 to 20 minutes in the preheated oven, until the filling is set and set. In a large bowl, combine the chocolate chips and butter. Spread over the top of the baked casserole, and sprinkle the remaining buttermilk on top.
Combine the cream cheese, eggs, 1/2 cup of sugar, and vanilla extract in a 1/4 cup butter. Spread over the entire bottom of the casserole.
Bake 20 to 30 more minutes in the preheated oven, until the filling is set and the casserole edges are golden. Cool completely on wire rack.