Heat oven to 350F. Melt butter in a bowl in a microwave. Crush graham crackers in a blender into fine crumbs. (See Notes.) In a 9x13 inch pan, mix together butter and graham cracker crumbs until well blended, then press into the bottom of the pan.

Layer chocolate chips in pan, then walnuts, and then pour sweetened condensed milk over all pan contents. Top with coconut, then sprinkle with leftover chocolate chips and walnuts. Bake for 18-20 minutes, or until coconut starts to turn a light golden brown. Allow to cool, then cut into squares.

Chocolate Chips  Use milk chocolate chips for better flavor, not semi-sweet chocolate, even if in the regular size. The original recipe calls for "jumbo" chips, which may be difficult to find in milk chocolate. 

This recipe is insanely delicious and so easy. A favorite copy-cat recipe from Zupas.