01 -
Preheat the oven to 350°F. Grease or line a 9x13-inch baking pan with parchment paper to prevent sticking.
02 -
In a large mixing bowl, combine the chocolate cake mix, melted unsalted butter, and eggs. Stir until the mixture is well blended and thick.
03 -
Gently fold the chopped Oreo pieces, semi-sweet chocolate chips, and half of the Halloween M&M’s into the batter until evenly distributed.
04 -
Spread the batter evenly into the prepared pan. Sprinkle the remaining M&M’s along with any desired decorative sprinkles on top for a festive appearance.
05 -
Bake for 20 to 25 minutes, or until the center is set but remains slightly soft. Do not overbake to maintain a fudgy texture.
06 -
Allow the bars to cool completely in the pan before slicing into squares. Serve once completely cooled.