This is one of my families favorite holiday cookies and they are SUPER easy. They are best baked in a metal pan but glass works fine - just cook them a little longer.
16 graham crackers (about 2 cups) finely ground in food processor or blender
1 can sweetened condensed milk
1 tsp. vanilla
1 cup semi-sweet chocolate chips
Mix ingredients well in bowl. Press batter into a 9x9 reall well greased and floured pan. Bake at 375 degrees for 20 - 30 minutes. Cool in pan. Invert pan onto large cutting board sprinkled with powdered sugar. Cut into squares and roll in powdered sugar.