Preheat oven to 350 degrees and line a 9×13 inch baking dish with foil that’s been sprayed with cooking spray.
Place butter, cake mix, egg, oil and chocolate chips into a large mixing bowl, stirring to combine into dough. Gently stir in chopped Cadbury Eggs to combine. Transfer dough to prepared baking dish and press evenly. Bake for 25-30 minutes until baked through. Let cool for 30 minutes before cutting into squares. Serve and enjoy!